ABS built-in functions – functions in Python, that compute absolute values.

Accelerated life testing – testing mode applying burn-in conditions, aiming to simulate the ageing process and evaluating the time to wear-out.

Across-chip linewidth variation (ACLV) – the effect of changing the channel length variation within-die, caused by lithography limitations and other technological imperfections.

Across-chip mobility variation – the technique used to control the carrier mobility of ON current.

Active mask – a type of physical mask that defines all areas where p-, n-type of diffusion or transistor gates should be applied.

Activity factor – the probability that the circuit node switches between 0 and 1 states.

Active transistor state – transistor state, when a base-collector pn-junction is reverse-biased, and base-emitter is forward-biased. Read more.

Additive manufacturing – also called 3D printing, is a popular manufacturing way where the process starts with nothing, all needed materials are being added during manufacturing process.

Admittance – is a complex quantity, measured in Siemens, used in AC circuit analysis, inverse to admittance, and defined by the formulaY=1Z=G+jB. Here G is called AC conductance and B – susceptance. But, admittance is not reciprocal to resistance R in general case. Read more.

Ad hoc clock distribution network – a network where a clock is routed randomly with possibility equalised wire lengths or add buffers to equalise the delay.

Ad hoc testing – testing techniques aimed to decrease combinational explosion of testing, including the following techniques: partitioning large sequential circuits, adding multiplexers, test points and providing for easy state reset.

Adaptive body bias – ability of chips to compensate for systematic die-to-die threshold variations to improve performance and decrease leakage.

Admittance inverter – is an inverter designed to invert low admittance. It can be used to transform shunt-connected elements into series-connected elements and vice versa.

Admittance matrix [Y]– is a microwave network that connects currents and voltages the following way: I=YV.

Air wires – a term used in PCB design. This is thin straight lines representing connections that should be made. But these connections are not seen on the final PCB layout.

ALD (Atomic layer deposition) – is a thin film deposition technique when chemical layer #1 is attached to the surface, and chemical layer #2 is used to produce a thin layer of required mterial.

Alternating Current (AC) – (AC) is an electric current in which the flow of electric charge periodically reverses direction, whereas in direct current (DC, also dc), the flow of electric charge is only in one direction. The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage. AC is the form in which electric power is delivered to businesses and residences. The usual waveform of alternating current in most electric power circuits is a sine wave. In certain applications, different waveforms are used, such as triangular or square waves.

Ambient temperature – is the temperature of the surrounding area when natural cooling is operating without presence of the heatsink.

Ammeter – a tool for measuring an electrical current in the circuit. Usually connected in parallel to a circuit element.Read more.

Ampere’s Law – is an integral part of Maxwel’s equations, represented by the following equation: Hdl=tDdS+IdS=tDdS+I.

Amplifier – is an electronic device, performing amplification functions. Read more.

Analogue Signals – An analogue signal is any continuous signal for which the time-varying feature (variable) of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. For example, in an analogue audio signal, the instantaneous voltage of the signal varies continuously with the pressure of the sound waves. It differs from a digital signal, in which the continuous quantity is a representation of a sequence of discrete values which can only take on one of a finite number of values. The term analogue signal usually refers to electrical signals; however, mechanical, pneumatic, hydraulic, human speech, and other systems may also convey or be considered analogue signals.

Analogue-to-Digital Converter (ADC) – In electronics, an analogue-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analogue signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may also provide an isolated measurement such as an electronic device that converts an input analogue voltage or current to a digital number representing the magnitude of the voltage or current. Typically the digital output is a two’s complement binary number that is proportional to the input, but there are other possibilities.

Apparent power – is the product of rms current and rms voltage and used in specifying the rating of power equipment. Apparent power is the magnitude of complex power and can be found using the formula S=P2+P2reac.

Application layer protocols – protocols usually fetch the web pages, send emails and do Internet telephony. the most universal protocol is HTTP for web. It also used to communicate between IoT devices.

Application programming interface (API) – is the programming interface that allows communication with other software, not only users.

Application-Specific Integrated Circuit (ASIC) – An application-specific integrated circuit is an integrated circuit (IC) chip customised for a particular use, rather than intended for general-purpose use. For example, a chip designed to run in a digital voice recorder or a high-efficiency bitcoin miner is an ASIC. Application-specific standard product (ASSP) chips are intermediate between ASICs and industry standard integrated circuits like the 7400 series or the 4000 series ASIC chips are typically fabricated using metal-oxide-semiconductor (MOS) technology, as MOS integrated circuit chips.

ATEX – The ATEX directive consists of two EU directives describing what equipment and work space is allowed in an environment with an explosive atmosphere. ATEX derives its name from the French title of the 94/9/EC directive: Appareils destinés à être utilisés en ATmosphères EXplosives.

Attentuator – An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform. An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than 1.

Automatic optical inspection (AOI) – is the testing step of the automated assembly process when high-resolution camera inspects the PCB with its components.

Average gate power dissipation – is the average value for maximum allowable power dissipation when device is forward conducting between gate and cathode.

Average on-state current – is an average value of forward current that can be continuously applied to a device with a resistive or inductive load.

Average value – in the theory of signals is the mean voltage or current over the period of time. It can be expressed by the formula x(t)=1T0Tx(r)dr, where T is a period of a signal.

Average power –  is a time average of a periodic instaneous power p(t) function over one or more periods T and can be found using the formula P=1T0Tp(t)dt. Average power absorbed by a dc voltage source can be found using a formula Pavg=IavgVdc. Average power absorbed by a dc current source can be found using a formula Pavg=IdcVavg.


Band-Pass Filter (BPF) – is characterised with lower cut-off frequency and upper cut-off frequency. Read more.

Base (B) – is a lightly doped layer in BJT structure.

Bill of Materials (BOM) – A bill of materials or product structure (sometimes bill of material, BOM or associated list) is a list of the raw materials, sub-assemblies, intermediate assemblies, sub-components, parts, and the quantities of each needed to manufacture an end product. A BOM may be used for communication between manufacturing partners or confined to a single manufacturing plant. A bill of materials is often tied to a production order whose issuance may generate reservations for components in the bill of materials that are in stock and requisitions for components that are not in stock.

Bipolar junction transistor (BJT) – a three terminal semiconductor device, based on three layers of p and n layers, with different doping concentration. Read more.

Bluetooth Low Energy (BLE) – Bluetooth Low Energy (Bluetooth LE, colloquially BLE, formerly marketed as Bluetooth Smart) is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group (Bluetooth SIG) aimed at novel applications in the healthcare, fitness, beacons, security, and home entertainment industries. Compared to Classic Bluetooth, Bluetooth Low Energy is intended to provide considerably reduced power consumption and cost while maintaining a similar communication range. Mobile operating systems including iOS, Android, Windows Phone and BlackBerry, as well as macOS, Linux, Windows 8 and Windows 10, natively support Bluetooth Low Energy.

Branch – is part of an electric circuit, with two terminals connected to it. Read more.

Bridge rectifier – is a fully or half-controlled device, constructed with four thyristors or with two thyristors and two diodes. Read more.

Boost converter – is a step-up converter, consisting of voltage source, inductance, diode, controllable switch, capacitance and load resistance. Output voltage and current can be found using formulas Vout=11kVs, and Iout=(1k)Is. Here Vs and Is are voltage and current of a source, k is conduction duty.

Buck converter – is a step-down converter, consisting of voltage source, controllable switch, diode, inductor, capacitor and a load resistance. Output voltage and current can be found using a formulas Vout=kVs and Iout=kIs, here Vs and Is are source voltage and current, k is the conduction duty.

Buck-Boost Converter – The buck–boost converter is a type of DC-to-DC converter that has an output voltage magnitude that is either greater than or less than the input voltage magnitude. It is equivalent to a flyback converter using a single inductor instead of a transformer. Output voltage and current can be found using formulas Vout=k1kVs and Iout=1kkIs, where Vs and Is are source voltage and current, k is a conduction duty.


C – C is a general-purpose, procedural computer programming language supporting structured programming, lexical variable scope, and recursion, while a static type system prevents unintended operations. By design, C provides constructs that map efficiently to typical machine instructions and has found lasting use in applications previously coded in assembly language. Such applications include operating systems and various application software for computers, from supercomputers to embedded systems.

C++ – C++ is a general-purpose programming language created by Bjarne Stroustrup as an extension of the C programming language, or ‘C with Classes’. The language has expanded significantly over time, and modern C++ has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation. It is almost always implemented as a compiled language, and many vendors provide C++ compilers, including the Free Software Foundation, LLVM, Microsoft, Intel, Oracle, and IBM, so it is available on many platforms.

Capacitor – is a system of two conductors, where an isolated electric field is created between two equal conductors and opposite charges. Read more.

Capacitive displacement transducer – is an electromechanical device, transforming the vibration or displacement into electric current. For example, it is used in microphones.

CAPTURE – graphical interface program for simulation from a graphical representation of a circuit diagram.

Case temperature – is the temperature at the certain point on the case of the device.

Central Processing Unit (CPU) – A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that executes instructions that make up a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions. The computer industry has used the term ‘central processing unit’ at least since the early 1960s. Traditionally, the term ‘CPU’ refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

Clamped inductive load current – is the maximum repetitive current when IGBT can switch-off under the clamped inductive load. During the IGBT turn-on process the switching losses are raising.

Collector (C) – lightly doped layer in BJT structure. Read more.

Common-base configuration – transistor configuration where the base is common for input and output voltages. Read more.

Common-emitter configuration – transistor configuration where the emitter is common for input and output voltages. Read more.

Collector-emitter leakage current – specifies the leakage current of the IGBT at the certain voltage and certain temperature the the gate and emitter are shorted.

Collector-emitter saturation voltage – shows collector-emitter voltage drop in IGBT, and it depends on the gate voltage, collector current and temperature.

Complementary metal–oxide–semiconductor (CMOS) – Complementary metal–oxide–semiconductor (CMOS), also known as complementary-symmetry metal–oxide–semiconductor (COS-MOS), is a type of MOSFET (metal–oxide–semiconductor field-effect transistor) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. CMOS technology is used for constructing integrated circuit (IC) chips, including microprocessors, microcontrollers, memory chips (including CMOS BIOS), and other digital logic circuits. CMOS technology is also used for analog circuits such as image sensors (CMOS sensors), data converters, RF circuits (RF CMOS), and highly integrated transceivers for many types of communication.

Complete response – in electronics theory is a combination of natural and forced responses x(t)=xn(t)+xf(t).

Complex power – is the sum of real and reactive power of AC circuit and can be found using a formula S=P+jPreac=Vrms(Irms)*.

Computer Numerical Control (CNC) – Computer numerical control, and commonly called CNC) is the automated control of machining tools (drills, boring tools, lathes) and 3D printers by means of a computer. A CNC machine processes a piece of material (metal, plastic, wood, ceramic, or composite) to meet specifications by following a coded programmed instruction and without a manual operator.

Computational thinking – is a process of defining the problem and formulating automated solutions. Read more.

Conductance – is the property of the circuit element material, that is inverse to its resistance, measured in Siemens (S). G=1R. Ohm law with conductance is V=GI.

Conductor – material, containing electrons that can freely move from atom to atom due to weak bond with the nucleus.

Constrained application protocol (CoAP)– is a protocol designed for the same purpose as HTTP, but for networks without TCP.

Contact thermal resistance – is a thermal resistance between the surface of the device case and the heatsink.

Continuous collector current – sets the dc current value needed to set up junction temperature of IGBT to its maximum. The datasheet usually specifies this parameter for 25° and 150°.

Coulomb (C) – is the unit of charge. 1C =1Asec. Coulomb is an amount of electricity flowing through the piece of circuit within a second, while current is equal to 1 Ampere.

Cuk converter – is the electronic device, consisting of DC input voltage source, input inductor, controllable switch, capacitor, diode, filter inductor and diode and a load resistor. The main advantage of this converter is continuous current on the input and output of converter.

Current divider – is a concept, used in the circuit theory, that states that current in a parallel circuit divides in an inverse proportion to the resistances of element connected in parallel. Elements of circuit are connected in parallel if they are all experiencing identical voltage through them. The current divider rule is expressed by the formula in=1Rn1R1+...+1RniS, where iS is the current of a current source.

Current-square time – is a maximum, non-repetitive, on-state, short-time thermal capacity  of the device.

Cut-off transistor state – transistor state, when the collector-base and emitter-base pn-junctions are reverse-biased – transistor is off. Read more.


DC chopper – is a series connection of DC input voltage source , controllable switch and load resistor. The DC step-down choppers are widely used in DC drives.

DC forward blocking voltage – is a maximum value for anode to cathode forward voltage, when the gate is open circuited.

DC-to-DC Converter – A DC-to-DC converter is an electronic circuit or electromechanical device that converts a source of direct current (DC) from one voltage level to another. It is a type of electric power converter. Power levels range from very low (small batteries) to very high (high-voltage power transmission).

DC reverse blocking voltage – is a maximum value of DC anode to cathode reverse voltage, when the gate is open circuited.

Dependent source – are sources, that are dependent on some parameters of the system. Read more.

Digital Signal Processor (DSP) – A digital signal processor (DSP) is a specialised microprocessor (or a SIP block) chip, with its architecture optimised for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio signal processing, telecommunications, digital image processing, radar, sonar and speech recognition systems, and in common consumer electronic devices such as mobile phones, disk drives and high-definition television (HDTV) products.

Digital-to-Analogue Converter (DACs) – In electronics, a digital-to-analogue converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analogue signal. An analogue-to-digital converter (ADC) performs the reverse function. There are several DAC architectures; the suitability of a DAC for a particular application is determined by figures of merit including: resolution, maximum sampling frequency and others. Digital-to-analogue conversion can degrade a signal, so a DAC should be specified that has insignificant errors in terms of the application.

DIN-Rail – A DIN-Rail is a metal rail of a standard type widely used for mounting circuit breakers and industrial control equipment inside equipment racks. These products are typically made from cold rolled carbon steel sheet with a zinc-plated or chromated bright surface finish. Although metallic, they are meant only for mechanical support, and are not used as a busbar to conduct electric current, although they may provide a chassis grounding connection.

Direct Current (DC) – Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries, power supplies, thermocouples, solar cells, or dynamos. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A term formerly used for this type of current was galvanic current. Direct current may be obtained from an alternating current supply by use of a rectifier, which contains electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alternating current with an inverter or a motor-generator set.

Direct Random Access Memory (DRAM) – Dynamic random-access memory (DRAM) is a type of random access semiconductor memory that stores each bit of data in a memory cell consisting of a tiny capacitor and a transistor, both typically based on metal-oxide-semiconductor (MOS) technology. The capacitor can either be charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. The electric charge on the capacitors slowly leaks off, so without intervention the data on the chip would soon be lost. To prevent this, DRAM requires an external memory refresh circuit which periodically rewrites the data in the capacitors, restoring them to their original charge. This refresh process is the defining characteristic of dynamic random-access memory, in contrast to static random-access memory (SRAM) which does not require data to be refreshed. Unlike flash memory, DRAM is volatile memory (vs. non-volatile memory), since it loses its data quickly when power is removed. However, DRAM does exhibit limited data remanence.

Distortion factor – is the ratio of the rms value of the fundamental frequency to the total rms value.

Distributed parameter system – is a concept in the electric theory where voltages and currents can vary in magnitude and phase over the system length. It shows the reduction in power factor due to non sinusoidal

Drift – movement of free electrons when voltage is applied to a conductor.


Effective voltage (for periodic voltage) – is a voltage that is effective as a dc voltage in supplying average power.

Electric charge – is a feature of matter that causes a force when placed into an electromagnetic field. Read more.

Electric current is a flow of electric charge. Read more.

Electric polarisation – is a polarisation vector Pe described by the formula D=ε0E+Pe. Here when the electric field E is applied to a dielectric material, it makes atoms and molecules to create additional dipole moments Pe amplifying the total displacement flux. In linear dielectric the polarisation vector can be linear Pe=ε0χeE, where χe is susceptability.

Electrical power – is the rate of transferring energy by electric circuit during a unit of time. Read more.

Electrically Erasable Programmable Read-Only Memory (EEPROM) – EEPROM (also E2PROM) stands for electrically erasable programmable read-only memory and is a type of non-volatile memory used in computers, integrated in microcontrollers for smart cards and remote keyless systems, and other electronic devices to store relatively small amounts of data but allowing individual bytes to be erased and reprogrammed. EEPROMs are organised as arrays of floating-gate transistors. EEPROMs can be programmed and erased in-circuit, by applying special programming signals. Originally, EEPROMs were limited to single byte operations, which made them slower, but modern EEPROMs allow multi-byte page operations. An EEPROM has a limited life for erasing and reprogramming, now reaching a million operations in modern EEPROMs. In an EEPROM that is frequently reprogrammed, the life of the EEPROM is an important design consideration.

Electromagnetic Compatibility (EMC) – Electromagnetic compatibility (EMC) is the ability of electrical equipment and systems to function acceptably in their electromagnetic environment, by limiting the unintentional generation, propagation and reception of electromagnetic energy which may cause unwanted effects such as electromagnetic interference (EMI) or even physical damage in operational equipment. The goal of EMC is the correct operation of different equipment in a common electromagnetic environment. It is also the name given to the associated branch of electrical engineering.

Electromagnetic Interference (EMI) – Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a data path, these effects can range from an increase in error rate to a total loss of the data. Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares, and auroras (northern/southern lights). EMI frequently affects AM radios. It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy and atmospheric science.

Embedded Electronics – An embedded system is a controller with a dedicated function within a larger mechanical or electrical system, often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. Embedded systems control many devices in common use today. Ninety-eight percent of all microprocessors manufactured are used in embedded systems.

Emitter (E) – heavily doped layer in the structure of BJTs. Read more.

Energy – is an integral of instaneous power p(t) over the desired time interval, can be calculated using the formula W=t1t2p(t)dt.

Energy stored in an inductor – the amount of energy, that can be described by formula W(t)=LI2(t)2

Ethernet – Ethernet is a family of computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardised in 1983 as IEEE 802.3. Ethernet has since retained a good deal of backward compatibility and has been refined to support higher bit rates, a greater number of nodes, and longer link distances. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI and ARCNET.

Extrinsic semiconductor – is a semiconductor where electrical properties are due to impurities in their structure. Impurities can create additional  energy levels in a forbidden band. Impurities in a semiconductor can be two types – replacement and implementation. Read more.


Fall time – term used in application to IGBTs, and specifies the time required for collector current to decline from 90% to 10% of its initial value.

Farad (F) – is the unit of capacitance, represented by the formula1F = 1CV.

Field-effect transistor – is a type of transistor that plays the role of the voltage-controlled amplifier. Read more.

Field Programmable Gate Array (FPGA) – A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturing – hence ‘field-programmable’. The FPGA configuration is generally specified using a hardware description language (HDL), similar to that used for an application-specific integrated circuit (ASIC). (Circuit diagrams were previously used to specify the configuration, as they were for ASICs, but this is increasingly rare). FPGAs contain an array of programmable logic blocks, and a hierarchy of reconfigurable interconnects that allow the blocks to be ‘wired together’, like many logic gates that can be inter-wired in different configurations. Logic blocks can be configured to perform complex combinational functions, or merely simple logic gates like AND and XOR. In most FPGAs, logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory.

Filter – four-terminal devices that serve to transfer electrical current between the source and load in a certain frequency range. Read more.

First generation converters – are classical converters performing a single quadrant mode. They can be separated into six categories including the following: fundamental topologies (buck converter, boost converter, buck-boost converter), developed topologies (positive output Lio-converter, double-output Luo-converter, Cut converter, SEPIC), transformer-type topologies (forward converter, push-pull converter, fly-back converter, half-bridge converter, bridge converter, ZETA), VL topologies (self-lift converters, positive output Luo-converters, negative output Luo-converters, double output Luo-converters), SL topologies (positive output SL Luo-converters, negative output SL Luo-converters, positive output cascade boost converter, negative output cascade boost converter),und ultra-lift Luo-converter.

First-order circuit – is a general example of a circuit consisting of a combination of resistors connected to a single energy-storage elements (inductors or capacitors).

First-order ordinary differential equation – is an equation of the form a1dx(t)dt+a0x(t)=f(t), where a1, a0are constants and f(t) is a forcing function.

First-order system – is a system that can store energy in one certain form and dissipate  it. You can see first-order system very frequently in a real world.

Flash Memory – Flash memory is an electronic (solid-state) non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory are named after the NAND and NOR logic gates. The individual flash memory cells, consisting of floating-gate MOSFETs (floating-gate metal-oxide-semiconductor field-effect transistors), exhibit internal characteristics similar to those of the corresponding gates.

Flyback Converter – The flyback converter is used in both AC/DC and DC/DC conversion with galvanic isolation between the input and any outputs. The flyback converter is a buck-boost converter with the inductor split to form a transformer, so that the voltage ratios are multiplied with an additional advantage of isolation. When driving for example a plasma lamp or a voltage multiplier the rectifying diode of the boost converter is left out and the device is called a flyback transformer.

Forced response – is the response to a particular forcing function, mathematically represented as the solution xf(t) of the following differential equation dxf(t)dt+1τxf(t)=f(t). In the example with electrical circuit, forced response describes the presence of active sources in the circuit.

Forcing function – is the function f(t) from the following differential equation a1dx(t)dt+a2x(t)=f(t).

Form factor – is the RMS value of a voltage or current to its average value, and can be calculated by the formula FF=VLVdc or FF=ILIdc.

Forward transconductance – is the parameter of IGBT that is measured with a small variation of the gate voltage. It linearly increases collector current at 100°, but with higher currents forward transconductance is decreasing. It means that current handling capability of IGBT is limited thermally. At higher temperatures forward transconductance decreases at lower currents.

Fourier theory – mathematical model representing signals as superposition of various sinusoidal signals characterised with different amplitude, phase and frequency.

Fourier series of sinusoids – is the way to express nonsinusoidal periodic waveforms. Trigonometrically it can be expressed using the formula f(t)=a0+n=1(ancosnω0t+bnsinnω0t), here a0=1TT2T2f(t)dtan=2TT2T2f(t)cosnω0tdt, bn=2TT2T2f(t)sinnω0tdt.

Frequency (of sinus wave signal) – is the amount of oscillations per second. Read more

Frequency response – scheme of the phase and magnitude of the system’s transfer function (function of frequency).

Full-wave rectifier – is a semiconductor device converting AC signal into a DC voltage. Read more.

Fundamental frequency – frequency of the signal, that can be found by the formula ω0=2πT0=2πf0. Fundamental frequency is an important part of the Fourier series representation presented the following way: f(t)=n=0Ancos(2πntT0+φn), here n is an integer, An amplitude, φn phase and T0 is a period of a signal.


Gain bandwidth product – is the gain of an operational amplifier after a particular point where the gain of the op-amp drops at a constant rate equal to the product of the gain multiplied by the frequency. 

Gallium Nitride (GaN) – Gallium nitride (GaN) is a binary III/V direct bandgap semiconductor commonly used in light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4eV affords it special properties for applications in optoelectronic, high-power and high-frequency devices. For example, GaN is the substrate which makes violet (405nm) laser diodes possible, without use of non-linear optical frequency-doubling. Its sensitivity to ionising radiation is low (like other group III nitrides), making it a suitable material for solar cell arrays for satellites. Military and space applications could also benefit as devices have shown stability in radiation environments.

Galvanic Isolation – Galvanic isolation is a principle of isolating functional sections of electrical systems to prevent current flow; no direct conduction path is permitted. Energy or information can still be exchanged between the sections by other means, such as capacitance, induction or electromagnetic waves, or by optical, acoustic or mechanical means. Galvanic isolation is used where two or more electric circuits must communicate, but their grounds may be at different potentials. It is an effective method of breaking ground loops by preventing unwanted current from flowing between two units sharing a ground conductor. Galvanic isolation is also used for safety, preventing accidental current from reaching ground through a person’s body.

Gate-Emitter threshold voltage – shows gate-emitter voltage range when IGBT is turned-on to conduct collector current. It raises linearly with gate-oxide thickness. And it raises as a square root of a p-base doping concentration.

Gating – is the process of turning the thyristor by injecting a current pulse into its gate.

Gate Turn-Off Thyristor (GTO) – is a three-terminal device, similar to SCR, but able to be turned off by the negative gate current.This device can be used in application where turn-on and turn-off switch control is required. Turn-off current is typically three times bigger than turn-on current.

Global Positioning System (GPS) – The Global Positioning System (GPS), originally NAVSTAR GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Air Force. It is a global navigation satellite system (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Obstacles such as mountains and buildings block the relatively weak GPS signals.

Graphical User Interface (GUI) – The graphical user interface is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, instead of text-based user interfaces, typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on a computer keyboard.

Graphics Processing Unit (GPU) – A graphics processing unit (GPU) is a specialised electronic circuit designed to rapidly manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mobile phones, personal computers, workstations, and game consoles. Modern GPUs are very efficient at manipulating computer graphics and image processing. Their highly parallel structure makes them more efficient than general-purpose central processing units (CPUs) for algorithms that process large blocks of data in parallel. In a personal computer, a GPU can be present on a video card or embedded on the motherboard. In certain CPUs, they are embedded on the CPU die.

Ground – is a reference point in an electric circuit that allows the measurement of voltages in a circuit. Read more.

Half-wave rectifier – is a semiconductor device converting AC signal into a DC voltage. Read more.

Heat sink – A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device’s temperature at optimal levels. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light emitting diodes (LEDs), where the heat dissipation ability of the component itself is insufficient to moderate its temperature.

Helmholtz equation – is the wave equation, used in the RF and MW theory, can be written for electric Eand magnetic H fields 2E+ω2μεE=0 and 2H+ω2μεH=0. Here k=ωμε is the magnetic propagation.

Hertz (Hz) – is a unit of natural frequencyf, equal to cycles per second. Though in the theory of signals we usually use frequency ω in units of radian per second. These two frequencies are interconnected by the relationship ω=2πf.

Homogenous solution – same as natural solution.

IB – base current of transistor.

 IC – collector current of transistor.

IE – emitter current of transistor.

Ideal current source – electrical device, that provides certain currents to the circuit connected to it. The amount of voltage through the source depends on the circuit connected to the source.

Ideal voltage source – electrical device, that provides certain voltage across source terminals. the amount of voltage is not dependent on the current flowing through the source, but the amount of current depends on the circuit connected to the source.

Impedance – in the theory of electric circuits a complex resistance of a circuit element. Some circuit elements are characterised with the frequency-dependent  resistance. For example, inductors and capacitors in the circuit are also characterised with frequency-dependent resistance and can be found by the following formulas: ZL(ωL)=jωL and ZC(ωC)=1jωC correspondently. In the complex form impedance of the circuit can be presented the following way: Z(jω)=Re(jω)+Im(jω).

Independent source – is the electrical device, that can create certain amount of voltage or current, independently from connected to it circuit.

Inductance – is a circuit element that can store magnetic energy of magnetic field and can respond to EMF of the circuit. It is characterised by the inductance characteristics or magnetic flux – current characteristics. Read more

Inductor – An inductor, also called a coil or reactor, is a passive two-terminal electrical component which resists changes in electric current passing through it. It consists of a conductor such as a wire, usually wound into a coil. Energy is stored in a magnetic field in the coil as long as current flows. When the current flowing through an inductor changes, the time-varying magnetic field induces a voltage in the conductor, according to Faraday’s law of electromagnetic induction. According to Lenz’s law the direction of induced electromotive force (or “e.m.f.”) is always such that it opposes the change in current that created it. As a result, inductors always oppose a change in current, in the same way that a flywheel opposes a change in rotational velocity. Care should be taken not to confuse this with the resistance provided by a resistor.

Initial condition – in electronics related to the energy stored in the capacitor or inductor at the moment of time t=0. Initial condition is important parameter for evaluating the solution of differential equations.

Input/Output (I/O) – In computing, input/output or I/O (or, informally, io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system. Inputs are the signals or data received by the system and outputs are the signals or data sent from it. The term can also be used as part of an action; to ‘perform I/O’ is to perform an input or output operation. I/O devices are the pieces of hardware used by a human (or other system) to communicate with a computer. For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices. Devices for communication between computers, such as modems and network cards, typically perform both input and output operations.

Input capacitance – is  a term used in application to IGBT,  is the gate-emitter capacitance when collector is shorted to emitter.

Insulated-Gate Bipolar Transistor (IGBT) – An insulated-gate bipolar transistor (IGBT) is a three-terminal power semiconductor device primarily used as an electronic switch which, as it was developed, came to combine high efficiency and fast switching. It switches electric power in many modern appliances: variable-frequency drives (VFDs), electric cars, trains, variable speed refrigerators, lamp ballasts, air-conditioners and even stereo systems with switching amplifiers. Since it is designed to turn on and off rapidly, amplifiers that use it often synthesise complex waveforms with pulse-width modulation and low-pass filters. In switching applications modern devices feature pulse repetition rates well into the ultrasonic range – frequencies which are at least ten times the highest audio frequency handled by the device when used as an analogue audio amplifier.

Instaneous power – is a time-varying quantity, equal to the voltage across the device and current in it, and can be found using a formula p(t)=v(t)i(t). If p(t)>0. then device is absorbing power, when p(t)<0, then device is supplying power.

Integrated Circuit (IC) – An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or ‘chip’) of semiconductor material that is normally silicon. The integration of large numbers of tiny MOS transistors into a small chip results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete electronic components. The IC’s mass production capability, reliability, and building-block approach to circuit design has ensured the rapid adoption of standardised ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionised the world of electronics. Computers, mobile phones, and other digital home appliances are now inextricable parts of the structure of modern societies, made possible by the small size and low cost of ICs.

Internet of Things (IoT) is a system of devices – such as sensors – connected to the internet, that are transmitting and storing data to the Cloud. IoT can be differentiated by different parameters, such as elements of AI, connection protocols, sensors, and others. Read more

Intrinsic impedance – is the characteristic of the medium in the electromagnetic field, that can be found by the formula η=ωμk=με.

Inverter – is the type of static power converter, producing AC output waveform from the DC input.

Ion – not electrically balanced, but positively charged atom, that capable of attracting electron from another atom.

ISO 26262 – ISO 26262, titled ‘Road vehicles – Functional safety’, is an international standard for functional safety of electrical and/or electronic systems in production automobiles defined by the International Organisation for Standardization (ISO) in 2011. Functional safety features form an integral part of each automotive product development phase, ranging from the specification, to design, implementation, integration, verification, validation, and production release. The standard ISO 26262 is an adaptation of the Functional Safety standard IEC 61508 for Automotive Electric/Electronic Systems. ISO 26262 defines functional safety for automotive equipment applicable throughout the lifecycle of all automotive electronic and electrical safety-related systems.

I-V characteristic (Volt-Ampere characteristic) – is a functional relationship between voltage and current. This relationship also can tell us about the power dissipated by circuit element. Often the graphical representation of the relationship between voltage and current is a complex function. i=f(v), v=g(i).

Joule (J) – unit of energy, described by the formula 1J = 1 N*sec. From here Joule is the energy transmitted when the force 1N is applied through the distance of 1m.

Joule’s law – the time-average power dissipated in the volume V due to electric and magnetic losses or conductivity can be found by the formula PJL=δ2VE2dv+ω2V(εE2+μH2)dv.

Junction temperature – this range of temperatures specified in the electronic device datasheet usually shows the available range of junction temperatures during the device operation.

Junction-to-ambient thermal resistance – is a  thermal resistance between device junction and ambient temperature.

Junction-to-ambient thermal transient impedance – is a thermal transient impedance between ambient and the junction.

Junction-to-case thermal resistance –  is a thermal resistance between junction and the case.

Junction-to-case thermal transient impedance – is a thermal transient impedance between junction and the case.

Junction-to-sink thermal resistance – is the thermal resistance between junction and the heatsink.

Junction-to-sink thermal transient impedance – is a transient thermal impedance between the junction and the heatsink.

Kirchhoff’s current law (KCL) – is the principle in electronics, saying that the sum of the currents at the junction of several conductors in a circuit is equal to zero. k=1NIk=0

Kirchhoff’s voltage law (KVL) – is the principle in electronics, that saying that the total voltage in the closed loop in a circuit is equal to zero. Vkk=1N=0


Light Emitting Diode – A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The colour of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.

Lithium-ion Batteries – A lithium-ion battery or Li-ion battery (abbreviated as LIB) is a type of rechargeable battery. Lithium-ion batteries are commonly used for portable electronics and electric vehicles and are growing in popularity for military and aerospace applications. In the batteries, lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge, and back when charging.

Load – is an element of electric circuit that dissipates energy.

Local Area Network (LAN) – A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger geographic distance, but also generally involves leased telecommunication circuits. Ethernet and Wi-Fi are the two most common technologies in use for local area networks. Historical network technologies include ARCNET, Token ring, and AppleTalk.

Long-Term Evolution (LTE) – In telecommunication, Long-Term Evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies. It increases the capacity and speed using a different radio interface together with core network improvements. The standard is developed by the 3GPP (3rd Generation Partnership Project) and is specified in its Release 8 document series, with minor enhancements described in Release 9. LTE is the upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. The different LTE frequencies and bands used in different countries mean that only multi-band phones are able to use LTE in all countries where it is supported.

Loop – is a closed connection of several brunches.

LoRa – LoRa (Long Range) is a low-power wide-area network (LPWAN) technology. It is based on spread spectrum modulation techniques derived from chirp spread spectrum (CSS) technology. It was developed by Cycleo of Grenoble, France and acquired by Semtech the founding member of the LoRa Alliance.

Low-Power Wide-Area Network (LPWAN) – A low-power wide-area network (LPWAN) or low-power wide-area (LPWA) network or low-power network (LPN) is a type of wireless telecommunication wide area network designed to allow long-range communications at a low bit rate among things (connected objects), such as sensors operated on a battery. The low power, low bit rate and intended use distinguish this type of network from a wireless WAN that is designed to connect users or businesses, and carry more data, using more power. The LPWAN data rate ranges from 0.3kbit/s to 50kbit/s per channel. A LPWAN may be used to create a private wireless sensor network, but may also be a service or infrastructure offered by a third party, allowing the owners of sensors to deploy them in the field without investing in gateway technology.

Lumped parameter system – is a concept in electric theory, where voltage and current do not vary along to a system dimensions.


Magnetic polarisation – when magnetic field applied to a magnetic material, magnetic dipole moments are aligning, producing magnetic polarisationPm. Magnetic field in this case will beB=μ0(H+Pm). When magnetic material is linearPm=χmHχmhere is magnetic susceptibility.

Maximum power dissipation – this parameter shows the required power dissipation needed to raise IGBT junction temperature to its maximum value of 150° keeping the case temperature at the value of 25°.

MCT (MOS-controlled thyristor) – is a device, consisting of SCR and two MOSFETs, functionally similar to GTO, but without requirement of high turn-off gate current. MCT turns on and off by establishing a proper voltage value from gate to cathode.

Mesh – is the loop with no loops in there.

Mesh-Current method – is a method of analysis in circuit theory, based on calculation of mesh currents as independent variables.

Metal-Oxide-Semiconductor-Field-Effect Transistor (MOSFET) – The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of transistor used for amplifying or switching electronic signals. Although the MOSFET is a four-terminal device with source (S), gate (G), drain (D), and body (B) terminals, the body (or substrate) of the MOSFET is often connected to the source terminal, making it a three-terminal device like other field-effect transistors. Because these two terminals are normally connected to each other (short-circuited) internally, only three terminals appear in electrical diagrams. The MOSFET is by far the most common transistor in both digital and analog circuits, though the bipolar junction transistor was at one time much more common.

Microcontroller (MCU) – A microcontroller (MCU for microcontroller unit) is a small computer on a single metal-oxide-semiconductor (MOS) integrated circuit chip. In modern terminology, it is similar to, but less sophisticated than, a system on a chip (SoC); an SoC may include a microcontroller as one of its components. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Program memory in the form of ferroelectric RAM, NOR flash or OTP ROM is also often included on chip, as well as a small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications consisting of various discrete chips.

MicroLED – microLED, also known as micro-LED, mLED or µLED, is an emerging flat-panel display technology. microLED displays consist of arrays of microscopic LEDs forming the individual pixel elements. When compared with widespread LCD technology, microLED displays offer better contrast, response times, and energy efficiency. Along with OLEDs, microLEDs are primarily aimed at small, low-energy devices such as smartwatches and smartphones. OLED and microLED both offer greatly reduced energy requirements when compared to conventional LCD systems while also offering an infinite contrast ratio. Unlike OLED, microLED is based on conventional gallium nitride (GaN) LED technology, which offers far higher total brightness than OLED produces, as much as 30 times, as well as higher efficiency in terms of lux/W and thus lower power consumption than OLED. OLED also suffers from screen burn-in, while microLED does not, but microLED displays cannot be made flexible or transparent like OLED displays can.

Microelectromechanical systems (MEMS) – Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems is the technology of microscopic devices, particularly those with moving parts. It merges at the nanoscale into nanoelectromechanical systems (NEMS) and nanotechnology. MEMS are also referred to as micromachines in Japan and microsystem technology (MST) in Europe.

Microprocessor without Interlocked Pipelined Stages (MIPS) – MIPS (Microprocessor without Interlocked Pipelined Stages) is a reduced instruction set computer (RISC) instruction set architecture (ISA):A-1:19 developed by MIPS Computer Systems, now MIPS Technologies, based in the United States. There are multiple versions of MIPS: including MIPS I, II, III, IV, and V; as well as five releases of MIPS32/64 (for 32- and 64-bit implementations, respectively). The early MIPS architectures were 32-bit only; 64-bit versions were developed later. As of April 2017, the current version of MIPS is MIPS32/64 Release 6. MIPS32/64 primarily differs from MIPS I–V by defining the privileged kernel mode System Control Coprocessor in addition to the user mode architecture.


NAND Flash – Flash memory is an electronic (solid-state) non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory are named after the NAND and NOR logic gates. The individual flash memory cells, consisting of floating-gate MOSFETs (floating-gate metal-oxide-semiconductor field-effect transistors), exhibit internal characteristics similar to those of the corresponding gates.

Nanoelectronics – Nanoelectronics refers to the use of nanotechnology in electronic components. The term covers a diverse set of devices and materials, with the common characteristic that they are so small that inter-atomic interactions and quantum mechanical properties need to be studied extensively. Some of these candidates include: hybrid molecular/semiconductor electronics, one-dimensional nanotubes/nanowires (e.g. Silicon nanowires or Carbon nanotubes) or advanced molecular electronics.

Nanoelectromechanical systems (NEMS) – Nanoelectromechanical systems (NEMS) are a class of devices integrating electrical and mechanical functionality on the nanoscale. NEMS form the next logical miniaturisation step from so-called microelectromechanical systems, or MEMS devices. NEMS typically integrate transistor-like nanoelectronics with mechanical actuators, pumps, or motors, and may thereby form physical, biological, and chemical sensors. The name derives from typical device dimensions in the nanometer range, leading to low mass, high mechanical resonance frequencies, potentially large quantum mechanical effects such as zero point motion, and a high surface-to-volume ratio useful for surface-based sensing mechanisms. Applications include accelerometers and sensors to detect chemical substances in the air.

Natural solution – is the solution of the differential equation a1dx(t)dt+a2x(t)=f(t) when forcing function f(t) is set equal to zero, so the differential equation looks a1dx(t)dt+a2x(t)=0

Near-Field Communication (NFC) – Near-field communication (NFC) is a set of communication protocols that enable two electronic devices, one of which is usually a portable device such as a smartphone, to establish communication by bringing them within 4 cm (1​1⁄2 in) of each other. NFC devices are used in contactless payment systems, similar to those used in credit cards and electronic ticket smart cards and allow mobile payment to replace or supplement these systems. This is sometimes referred to as NFC/CTLS (contactless) or CTLS NFC. NFC is used for social networking, for sharing contacts, photos, videos or files. NFC-enabled devices can act as electronic identity documents and keycards. NFC offers a low-speed connection with simple setup that can be used to bootstrap more capable wireless connections.

Newton (N) – is the unit of force, described by the formula 1N = 1kg*1msec2. 1 N is the amount of force applied to  the object with mass of 1 kg, makes object move with acceleration of 1msec2.

Node – is a junction of several branches.

Node-Voltage Method – is a method of analysis in circuit theory, based on calculation of node voltages as independent variables. For the circuit containing N nodes its possible to construct N-1 independent equations.

Non-linear circuit elements – are circuit elements, characterised with non-linear functional  relationshipi=f(v).

Non-volatile Memory (NVM) – Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retrieve stored information even after having been power cycled. In contrast, volatile memory needs constant power in order to retain data. Examples of non-volatile memory include flash memory, read-only memory (ROM), ferroelectric RAM, most types of magnetic computer storage devices (e.g. hard disk drives, floppy disks, and magnetic tape), optical discs, and early computer storage methods such as paper tape and punched cards.


Ohm – is a resistance unit, Ω, and defined by the formula 1Ω=1VA.

Ohmmeter – is a device, that can measure resistance of a circuit elements, connected in parallel.

Ohm’s law – Ohm’s law states that the voltage across the circuit element is proportional to the current flowing through it. V=RI. The aspect of this ratio is called resistance and measured in Ohms (Ω).

One-phase current – is a current that can be described with a formula . Read more

One-port network – is a representation of a part of a circuit as a two-terminal device, characterised by IV characteristic.

Open circuit voltage – is a Thenevin equivalent current.

Optical communication systemis a system characterised with a large capacity to carry information. It can be used  in any application where transfer of the information is required from one place to another. And can be classified into two categories – guided and unguided optical systems. Read more.

Optoelectronics – Optoelectronics (or optronics) is the study and application of electronic devices and systems that source, detect and control light, usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light. Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers, or instruments that use such devices in their operation. Electro-optics is often erroneously used as a synonym, but is a wider branch of physics that concerns all interactions between light and electric fields, whether or not they form part of an electronic device.

Organic Light Emitting Diode (OLED) – An organic light-emitting diode (OLED or Organic LED), also known as an organic EL (organic electroluminescent) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, portable systems such as smartphones, handheld game consoles and PDAs. A major area of research is the development of white OLED devices for use in solid-state lighting applications.

Original Equipment Manufacturer (OEM) – A somewhat misleading term used to describe a company that has a special relationship with computer and IT producers. OEMs are typically manufacturers who resell another company’s product under their own name and branding. When a computer technology producer manufacturers its product, for example, a computer graphics card, they will usually make two or more versions of the product. One version is distributed by the manufacturer direct to the consumer retail market, using its own branding and offering its own warranty and support. Other versions of the manufactured product will be distributed through the manufacturer’s OEM and authorised reseller distribution channels. Usually OEM products are the same quality as the retail versions, but warranties may be different, the manual and bundled software may be non-existent, and the cables and connectors required for installation might not be included. In some cases it may be large quantities of the product purchased in bulk by the OEM for mass-production of pre-built systems.

Output capacitance – specifying the collector-emitter capacitance, when the gate is shorted to emitter.

Overdamped solution – is the solution of the differential equation, expressed the following way xn(t)=K1eα1t+K2eα2t. Here constants α1=1τ1and α2=1τ2.


Passives – Passivity is a property of engineering systems, used in a variety of engineering disciplines, but most commonly found in analogue electronics and control systems. A passive component, depending on field, may be either a component that consumes (but does not produce) energy (thermodynamic passivity), or a component that is incapable of power gain (incremental passivity). A component that is not passive is called an active component. An electronic circuit consisting entirely of passive components is called a passive circuit (and has the same properties as a passive component). Used out-of-context and without a qualifier, the term passive is ambiguous. Typically, analogue designers use this term to refer to incrementally passive components and systems, while control systems engineers will use this to refer to thermodynamically passive ones.

Peak collector repetitive current – describes the high peak current that can IGBT can hold off under the transient conditions.

Peak forward blocking voltage – determines the repetitive peak off-state anode to cathode voltage, when the gate terminal is open circuited, or with certain reverse voltage between the gate and cathode.

Peak forward gate current – is the peak value of current flowing forward direction between gate and cathode.

Peak forward gate voltage – is the peak value of the voltage in forward direction between gate and cathode.

Peak forward leakage current – is a peak value of off-state current through a device in conditions of applied forward voltage.

Peak gate reverse power dissipation – is the peak value of allowable power dissipation in the reverse direction between gate and cathode within certain period of time.

Peak on-state current – is a peak-value of a non-repetitive on-state current (with 50 or 60 Hz).

Peak on-state voltage – is a peak value of a voltage drop, when on-state current is applied (50 or 60 Hz).

Peak reverse blocking voltage – is a repetitive peak reverse anode to cathode voltage applicable on each cycle, where the gate terminal is open circuited.

Peak reverse gate voltage – is the peak value of the reverse voltage between gate and cathode.

Peak reverse leakage current – is a peak value for reverse current when in the condition of applied reversed voltage.

Periodic signals – a class of signals, used as an approximation of real processes, and described by the equation f(t)=f(t+nT), n=0,1,2...and T is a period of f(t).

Phasor – is complex vector that expresses a sinusoid signal, represented by the expression Acos(ωt+ϕ)=ReAej(ωt+ϕ).

Polarisation (of a plane wave) – is the direction of the vector of electric field. It can be fixed or change with time.

Poynting theorem – is an energy conservation law for electromagnetic fields and sources. Let’s consider an electromagnetic energy source, that can store electric and magnetic energy, can carry a power and transmit it or dissipate it. Then Poynting theorem says, that complex power Ps=12V(E·J*s+H*·Ms)dv, here Js and Ms are magnetic and electric sources.

Poynting vector – is the quantity that can be derived from the Poynting theorem and represented by the formula S=E×H*.

Positive-output Luo-converter – is a step down/up converter, consisting of the voltage source, resistive load, controllable switch, two inductances, two conductances, and diode. This converter can work in discontinuous mode. It’s output voltage and current can be calculated using  the formulas Vout=k1kVs and Iout=1kkIs, where Vs and Is are source voltage and current, k is the conduction duty.

Power (or electrical power) – is the work per unit of time. P=At. The power generated or dissipated by the circuit element, equal to the voltage and current through the element. Power is measured in Watts (W). P=VI. Power can have positive or negative sign. If the power sign in positive, then the charge was displaced from the higher potential to lower potential. If the power sign is negative, then the charge was displaced from the lower potential to higher potential. Direction of charge displacement indicated by the voltage sign.

Power factor – is the ratio of average power and apparent power, can be found using a formula: pf=PVrmsIrms.

Power Management Integrated Circuits (PMIC) – Power management integrated circuits (power management ICs or PMICs or PMU as unit) are integrated circuits for power management. Although PMIC refers to a wide range of chips (or modules in system-on-a-chip devices), most include several DC/DC converters or their control part. A PMIC is often included in battery-operated devices such as mobile phones and portable media players to decrease the amount of space required.

Power stored in the inductor – can be found by the formula P(t)=t(LI2(t)2).

Principle of superposition – is the principle in the theory of circuits, stating that in the circuit with N sources, every branch voltage an current is the sum of N voltages and currents that can be computed the following way: all but one source should be set equal to zero, and solve the circuit containing only one source.

Printed Circuit Board (PCB) – A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.

Programmable Logic Controller (PLC) – A programmable logic controller (PLC) or programmable controller is an industrial digital computer which has been ruggedised and adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability control and ease of programming and process fault diagnosis. PLCs were first developed in the automobile manufacturing industry to provide flexible, ruggedised and easily programmable controllers to replace hard-wired relays, timers and sequencers. Since then, they have been widely adopted as high-reliability automation controllers suitable for harsh environments. A PLC is an example of a ‘hard’ real-time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation will result.

Propagation constant – see wave number.

Python – Python is an interpreted, high-level, general-purpose programming language. Created by Guido van Rossum and first released in 1991, Python’s design philosophy emphasises code readability with its notable use of significant whitespace. Its language constructs and object-oriented approach aim to help programmers write clear, logical code for small and large-scale projects.

PSPICE – is a commercially available adaptation of SPICE, suitable for personal computers.

PWM DC-DC full-bridge converter – is the electronic device consisting of voltage source, four controllable switches, two diodes, transformer and a load.

PWM DC-DC push-pull converter – is the electronic device consisting of two controllable switches, two diodes, voltage source, transformers and a load. The switches operates shifted here. When first switch is on, corresponding diode conducts, and vice versa for the second switch. When both switches are off – diodes are on and share the current.

Quarter-wave impedance transformer – is a device that matches the transmission line and the impedance. Read more.

Radio Frequency (RF) – Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around 20 kHz to around 300 GHz. This is roughly between the upper limit of audio frequencies and the lower limit of infrared frequencies; these are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range.

Radio-Frequency Identification (RFID) – Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves. Active tags have a local power source (such as a battery) and may operate hundreds of meters from the RFID reader. Unlike a barcode, the tags don’t need to be within the line of sight of the reader, so it may be embedded in the tracked object. RFID is one method of automatic identification and data capture (AIDC).

Random Access Memroy (RAM) – Random-access memory (RAM) is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.

Reactance – is a term used in connection to the complex impedance of the elements of the circuit. As soon as the complex impedance of the circuit can be written the following way: Z(jω)=Re(jω)+Im(jω).

Reactive power – is combined energy stored during the first half-cycle and recovered by the second half-cycle. Reactive power is usually applied to the combined energy of inductor or capacitor, and can be found using a formula Preac=VrmsIrmscos(θφ).

Real-Time Clock (RTC) – A real-time clock (RTC) is a computer clock (most often in the form of an integrated circuit) that keeps track of the current time. Although the term often refers to the devices in personal computers, servers and embedded systems, RTCs are present in almost any electronic device which needs to keep accurate time.

Real-Time Operating System (RTOS) – A real-time operating system (RTOS) is an operating system (OS) intended to serve real-time applications that process data as it comes in, typically without buffer delays. Processing time requirements (including any OS delay) are measured in tenths of seconds or shorter increments of time. A real-time system is a time bound system which has well defined fixed time constraints. Processing must be done within the defined constraints or the system will fail. They either are event driven or time sharing. Event driven systems switch between tasks based on their priorities while time sharing systems switch the task based on clock interrupts. Most RTOSs use a pre-emptive scheduling algorithm.

Rectification ratio – is a parameter showing the effectiveness of the rectification and  can be found using a formula δ=PdcPL.

Reflection coefficient – is the parameter describing amount of wave reflected in the medium, and can be found by the formula Γ=ηη0η+η0, where η=jwμγ is intrinsic impedance and γ=jωμε1jσωε is propagation constant.

Relays – A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal. Relays were first used in long-distance telegraph circuits as signal repeaters: they refresh the signal coming in from one circuit by transmitting it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

Resistance – is a element of a circuit, characterised by the volt-ampere characteristics of the circuit (corresponding to the resistor). Magnitude of resistance depends on the properties of material. Current flowing through the element may cause energy dissipation. Read more.

Resistance Strain Gauges – devices, used in engineering, that are bonded to the surface of the object. Their resistance varies depending on the surface strain of the object. These devices can be used to measure stress, force, torque, pressure.

Resistive Throttle Position Sensor (TPS sensor) – is the circuit element, providing variable resistance, depending on the position of the throttle valve.

Resistivity – is the property of the material, defining the resistance of the circuit element. It is denoted by the symbol ρ. Resistivity is opposite to the property, called conductivity. For a cylindrical resistive element, resistivity is described by the formula ρ=RSl, where R is the radius of the element, S is the square of its cross section, and l is its length.

Resistors – A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits. In electronic circuits, resistors are used to limit current flow, to adjust signal levels, bias active elements, and terminate transmission lines among other uses. High-power resistors, that can dissipate many watts of electrical power as heat, may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.

Restriction of Hazardous Substances Directive (RoHS) – The Restriction of Hazardous Substances Directive 2002/95/EC, (RoHS 1), short for Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment, was adopted in February 2003 by the European Union.

Reverse transfer capacitance – is a miller capacitance between gate and collector.

Ripple factor – is the measure of the ripple content, equal to the ratio of rms value of ac content of the load voltage to the average value. It can be found using a formula RF=VacVdc=FF21.

Rise time – term used in application to IGBT, is a time required for collector current to rise from 10% to 90% of its initial value.

RISC-V – RISC-V (pronounced ‘risk-five’) is an open-source hardware instruction set architecture (ISA) based on established reduced instruction set computer (RISC) principles. Unlike other academic designs which are optimised only for simplicity of exposition, the designers state that the RISC-V instruction set is for practical computers. It is said to have features to increase computer speed, yet reduce cost and power use. These include a load–store architecture, bit patterns to simplify the multiplexers in a CPU, simplified standards-based floating-point, a design that is architecturally neutral, and placing most-significant bits at a fixed location to speed sign extension. Sign extension is said to often be on the critical timing path.

RMS (root-mean-square) value – in the theory of signals is the value of the signal, taking into account fluctuations of the signal about its average value, and can be found by the formula xrms=1T0Tx(r)dr, where T is a period of a signal.

RMS on-state current – is a RMS value of on-state current that can be continuously applied to a device.

Rotating electrical machine – is a microelectromechanical system, operating on the laws of electric and magnetic fields, consisting of rotor, stator, and windings. One of the examples of microelectromechanical systems is rotating electric machines. The key role in the operation of electric machines is played by windings. Read More 


Second-order ordinary differential equation – is a differential equation of the forma2d2x(t)dt2+a1dx(t)dt+a0x(t)=F(t).

Semiconductors – are a class of materials characterised with electron conductivity. They are capable of changing their features depending on different external conditions (temperature, light, electromagnetic field and others). Semiconductors can be intrinsic and extrinsic. Read more.

Session Initiation Protocol (SIP) – The Session Initiation Protocol (SIP) is a signalling protocol used for initiating, maintaining, and terminating real-time sessions that include voice, video and messaging applications. SIP is used for signalling and controlling multimedia communication sessions in applications of Internet telephony for voice and video calls, in private IP telephone systems, in instant messaging over Internet Protocol (IP) networks as well as mobile phone calling over LTE (VoLTE).

Short-circuit current – is a Norton equivalent current.

Signalsare functions of one or several independent variables. There are two types of signals – discrete-time and continuous-time. Discrete-time signals are defined at the discrete moment of time and the mathematical function takes the discrete set of values. Read more.

Signal generator – is a device, allowing allowing a selection of waveform with amplitude and period.

Silicon Carbide (SiC) – Silicon carbide (SiC), also known as carborundum, is a semiconductor containing silicon and carbon. It occurs in nature as the extremely rare mineral moissanite. Synthetic SiC powder has been mass-produced since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite.

Silicon-controlled rectifier (SCR) – is a three-terminal device consisting of cathode, anode and gate, often synonymous to thyristor. In order to SCR conduct, the gate current should be applied in condition with positive anode-to-cathode voltage. It’s important for SCR operation that anode current remains positive.

Single-phase half-wave diode rectifier – is the device that converts AC signal into DC voltage. The simplest rectifier of this type consist of one diode, connected to secondary transformer, during the positive cycle of the transformer diode conducts, during the negative cycle diode stops conducting.

Single-phase full-wave rectifier – this device consists of centre-tapped transformer and two diodes. each diode conducts in certain cycle, what provides full rectification in the load.

Sink temperature – is a temperature of the certain point on the heatsink of the electronic device.

Skin depth – the depth to which most of the microwave power penetrates in the material, usually marked δs.

Solid State Drives (SSDs) – A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is also sometimes called a solid-state device or a solid-state disk, although SSDs lack the physical spinning disks and movable read-write heads used in hard drives (‘HDD’) or floppy disks.

Source – is an element of electric circuit, that provides energy. Can be several types.

Source transformation – is a procedure used in circuit analysis for calculating equivalent circuits based on replacing existing voltage and current sources.

SPICE – is a circuit simulation program, that was developed at the University of California at Berkeley.

Static Random Access Memory (SRAM) – Static random-access memory (static RAM or SRAM) is a type of semiconductor random-access memory (RAM) that uses bistable latching circuitry (flip-flop) to store each bit. SRAM exhibits data remanence, but it is still volatile in the conventional sense that data is eventually lost when the memory is not powered. The term static differentiates SRAM from DRAM (dynamic random-access memory) which must be periodically refreshed. SRAM is faster and more expensive than DRAM; it is typically used for CPU cache while DRAM is used for a computer’s main memory.

Storage temperature – is the range of temperatures specifying maximal and minimal temperatures allowable for storage of an electronic device without electrical connections.

Substractive manufacturing – is a manufacturing method, opposite to additive manufacturing, where material layers are being cut away where they are not needed. The example of subtractive manufacturing is laser cutting.

Supervisory Control and Data Acquisition (SCADA) – Supervisory Control and Data Acquisition (SCADA) is a control system architecture that uses computers networked data communications and graphical user interfaces(GUI) for high-level process supervisory management, but uses other peripheral devices such as programmable logic controller (PLC) and discrete Proportional Integral Differentiator (PID) controllers to interface with the process plant or machinery. The use of SCADA has been also considered for management and operations of project-driven-process in construction.

Surface resistance – is the resistance of the conductor in the layer between outside and skin depth level. Surface resistance of the conductor can be found by the formula Rs=1σδs.

System-on-Chip (SoC) – A system on a chip or system on chip (SoC or SOC) is an integrated circuit (IC) that integrates all components of a computer or other electronic system into a single chip. It may contain digital, analogue, mixed-signal, and often radio-frequency functions—all on a single chip substrate. SoCs are very common in the mobile electronics market because of their low power consumption. A typical application is in the area of embedded systems. The contrast with a microcontroller is one of degree. Microcontrollers typically have under 100KB of RAM (often just a few kilobytes) and often really are single-chip-systems, whereas the term SoC is typically used for more powerful processors, capable of running software such as the desktop versions of Windows and Linux, which need external memory chips (flash, RAM) to be useful, and which are used with various external peripherals. In short, for larger systems, the term system on a chip is hyperbole, indicating technical direction more than reality: a high degree of chip integration, leading toward reduced manufacturing costs, and the production of smaller systems. Many systems are too complex to fit on just one chip built with a processor optimised for just one of the system’s tasks.

System-on-Module (SoM) – A system on a module (SOM) is a board-level circuit that integrates a system function in a single module. It may integrate digital and analog functions on a single board. A typical application is in the area of embedded systems. Unlike a single-board computer, a SOM serves a special function like a system on a chip (SoC). The device integrated in the SOM typically requires a high level of interconnection for reasons such as speed, timing, bus-width etc., in a highly integrated module. There are benefits in building a SOM, as for SoC; one notable result is to reduce the cost of the base board or the main PCB. Two other major advantages of SOMs are design-reuse and that they can be integrated into many embedded computer application.

Switches – In electrical engineering, a switch is an electrical component that can ‘make’ or ‘break’ an electrical circuit, interrupting the current or diverting it from one conductor to another. Switch has an internal mechanism which removes or restores the conductive path when it is being operated. It may be operated manually, for example, a light switch or a keyboard button, may be operated by a moving object such as a door, or may be operated by some sensing element for pressure, temperature or flow.


The Thenevin Theorem – the circuit composed of ideal voltage/current sources and linear resistors can be represented by equivalent circuit with equivalent voltage source veq in series with equivalent resistance req.

The Norton theorem – the circuit composed of ideal voltage/current sources and linear resistors can be represented by equivalent circuit with equivalent current source ieq in parallel with equivalent resistance req .

TensorFlow – TensorFlow is a free and open-source software library for dataflow and differentiable programming across a range of tasks. It is a symbolic maths library, and is also used for machine learning applications such as neural networks. It is used for both research and production at Google.‍

Tera Operations Per Second (TOPS) – Tera Operations Per Second (TOPS) is a common performance metric used for high-performance SoCs. TOPS per watt extends that measurement to describe performance efficiency. The higher the TOPS per watt the better and more efficient a chip is.

Thyristor – is a three-terminal device used in some power electronic circuits, including silicon-controlled rectifier (SRC), the triac, the gate turn-off thyristor (GTO), MOS-controlled thyristor and others. Thyristors are known by their capability work with large currents and blocking voltages, but relatively low switching frequencies.

Time constant – is the constant parameterain the differential equationa1dx(t)dt+a2x(t)=f(t), herea=a2a1=1τ.

Time-Sensitive Networking (TSN) – Time-Sensitive Networking (TSN) is a set of standards under development by the Time-Sensitive Networking task group of the IEEE 802.1 working group. The TSN task group was formed in November 2012 by renaming the existing Audio Video Bridging Task Group and continuing its work. The name changed as a result of extension of the working area of the standardisation group. The standards define mechanisms for the time-sensitive transmission of data over deterministic Ethernet networks.

Transfer function – also known as a system function, that serves as a relationship between output and input amplitude.

Transformer utilisation factor – is the measure of the rate of rectifying current, equal to the ratio of the DC output power to the transformer power rating and can be found using a formula TUF=PdcVsIs.

Transient analysis – is the analysis among to describe the current or voltage behaviour between two steady-state conditions.

Transient peak-reverse blocking voltage – is a non-repetitive peak reverse anode to cathode voltage, during the time period less than 5ms, when the gate is open circuited.

Transient response – is the circuit response for application current or voltage. The example of a transient response is when a switch is on or off in a circuit.

Transient thermal impedance – the change of temperature difference between two specified points at the end of the time interval and at the beginning of this interval that is causing the change of the temperature difference.

Transmission coefficient – is the parameter, showing the amount of the electromagnetic wave, that was transmitted through the medium, and can be found by the formula Τ=1+Γ=2ηη+η0, where η=jωμγ is an intrinsic impedance and γ=jωμε1jσωε is propagation constant.

Triac – is a thyristor used to conduct current in both directions, that is functionally equivalent to two antiparallel SCRs.

Triggering – see gating.

Turn-off delay time – term used in application  to IGBTs, and it is a time between 90% of gate voltage and 10% of collector voltage.

Turn-on delay time – is the time defined as a time between 10% gate voltage and 10% of the final collector current.


Universal Asynchronous Receiver-Transmitter (UART) – A universal asynchronous receiver-transmitter (UART) is a computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. The electric signalling levels and methods are handled by a driver circuit external to the UART. A UART is usually an individual (or part of an) integrated circuit (IC) used for serial communications over a computer or peripheral device serial port. One or more UART peripherals are commonly integrated in microcontroller chips. A related device, the universal synchronous and asynchronous receiver-transmitter (USART) also supports synchronous operation.


VAR controller – is a circuit where thyristor is used to switch capacitors or inductors in order control reactive power in the system.

Vector network analyzer – two (or four channel) receiver, processing phase and magnitude of transmitted and reflected  waves from the network.

Volt (V) – unit of electric potential or voltage, described by the formula 1V=1WA=1JC. Volt is a difference in potential between two points in a conductor, where electrical current equal to 1A dissipates power of 1W.

Voltmeter – is a device for measuring voltage across the circuit element.

Voltage divider – is the concept used in the circuit theory, that allows to calculate the proportion of voltage drop distribution around the circuit, consisting of several resistances connected in series. The elements of circuit are connected in series if they identical current flows through every element. Voltage divided rule is represented by the formula vn=RnR1+...+RnvS, where vS is a voltage of a voltage source.


Wave equation – see Helmholtz equation.

Wavelength – is a distance between two subsequent maxima on the wave considered at a fixed time, and can be found with the formula λ=2πk=2πvfω.

Wave number – is a propagation constant in wave equation k=ωμε. Propagation constant can be also complex and defined by the formula γ=α+jβ=jωμε1jσωε, here α is attenuation constant and β is phase constant.

Watt (W) – unit of power, described by the formula 1W=1J1sec. Power can be described as a rate of transmitting the energy.

Wattmeter – is a measuring device that can provide measurement of power dissipated through the circuit element.

Water resistor – is a combination of metal electrode and electrolytic solution (dilute solution of copper sulfate in deionised water), that can hold high voltage from modulator and dissipate average power.

Well implants – high energy ions providing low-resistance path to contacts of a device.

Wheatstone bridge – is a resistive circuit, that is usually used in measurement circuits.

Wind energy – one of the greatest potentially type of energy, estimated as 300TW to 780TW. Most wind energy is available on the open ocean.

W-band communication range – is the frequency range 75-100GHz, used in satellite communications, millimetre-wave radars, and some other applications.

X-band communication range – is a 7.0 -11.2 GHz band of frequencies in MW region of electromagnetic spectrum. This frequency band is used in the radar engineering, satellite communication and other applications.
Yield – in electronics engineering marked as Y, is the probability that the electronic device will work. It is related to the failure probability X the following via the formula X=1Y. If there is N components in a system, the yield of the system Ys can be found by the formula Ys=YNc.

Zener diode – is a type of diode whose properties depend on the voltage avalanche properties. It is used for regulation and voltage reference.

Zigzag dipole antenna – is an element of a log-periodic dipole antenna.