Power Electronics

# Single-phase half-wave rectifiers This post tells about the single-phase half-wave rectifier, it waveforms and characteristics. A single-phase half-wave rectifier circuit is depicted below. This rectifier has a resistive load. This rectifier is the simplest form of diode single-phase rectifiers. Figure 1. Single-phase half-wave rectifier circuit.

During the positive part the sinus signal diode conducts, during the negative part the sinus signal diode stops conducting.  Let’s assume  that the voltage transformer is ${v}_{T}={v}_{max}\mathrm{sin}\left(\omega t\right)$, and the resistor voltage and resistance are ${v}_{R}$ and $R$, diode voltage is ${v}_{d}$. Then the wave forms for the diode are the following:

Figure 2. Voltage and current for the diode of the single-phase half-wave rectifier.

The resulting voltage and current of single-phase half-wave rectifier is  ${v}_{DC}=\frac{1}{T}{\int }_{0}^{T}{v}_{max}\mathrm{sin}\omega tdt=0.318{v}_{max}$, $\frac{{v}_{DC}}{R}={I}_{DC}$.

RMS is  $rmsi=\frac{{v}_{max}}{2R}$ .
Rectification ratio (maximum conversion ration) is $\eta =\frac{{P}_{DC}}{{P}_{R}}=\frac{{v}_{DC}{i}_{Dc}}{{v}_{R}{i}_{R}}=40.5%$.Form-factor $FF=\frac{{v}_{DC}}{{v}_{L}}=1.57$ .
Ripple factor $RF=\frac{{v}_{AC}}{{v}_{DC}}=\sqrt{F{F}^{2}–1}=1.21$.
Transformer utilisation factor $TUF=\frac{2{v}_{DC}{v}_{AC}}{{v}_{max}{i}_{max}}=0.286$
Digi-Key Electronics offers a great selection of single-phase half-wave rectifiers.