Characteristics of Full Wave Rectifier

Characteristics of Full Wave Rectifier

A Rectifier is an electrical device that converts alternating current (AC), which periodically reverse direction, to direct current (DC), which flows in only one direction. The process is known as Rectification. A full wave rectifier is a device which is used to rectify all the alternating current components in an alternating supply and make it purely a direct current.

Characteristics of full wave rectifier:

Ripple Factor: Ripple Factor is defined as the ratio of ripple voltage to the pure DC voltage.

The ripple factor is used to measure the number of ripples present in the output DC signal. A high ripple factor indicates a high pulsating DC signal while a low ripple factor indicates a low pulsating DC signal.

$$\gamma \,=\,\sqrt{{{\left( \frac{{{V}_{rms}}}{{{V}_{DC}}} \right)}^{2}}\,-\,1}$$.

Finally, we get γ = 0.48.

Form Factor: Form factor is the ratio of RMS value of current to the DC output current.

$$Form\,Factor\,=\,\frac{RMS\,\,Value\,\,of\,\,Current}{DC\,\,Output\,\,Current}$$.

The form factor of a full wave rectifier is 1.11.

DC Output Current: At the output load resistor RL, both the diode Dand diode D2currents flow in the same direction. So, the output current is the sum of D1 and D2 currents.

The current produced by $${{D}_{1}}\,=\,\frac{{{I}_{\max }}}{\pi }$$.

And the current produced by $${{D}_{2}}\,=\,\frac{{{I}_{\max }}}{\pi }$$.

So, the output current $$\left( {{I}_{DC}} \right)\,=\,\frac{2{{I}_{\max }}}{\pi }$$.

Where,

Imax = Maximum DC load current

Peak Inverse Voltage: Peak inverse voltage or peak reverse voltage is the maximum voltage a diode can withstand in the reverse bias condition. If the applied voltage is greater than the peak inverse voltage, the diode will be permanently destroyed.

The peak inverse voltage (PIV) = 2Vs max = 2Vsmax.

DC Output Voltage: The DC output voltage appeared at the load resistor RL is given as $${{V}_{DC}}\,\,=\,\,\frac{2{{V}_{\max }}}{\pi }$$.

Where,

Vmax = Maximum secondary voltage.

Root mean Square value of load current IRMS: The root mean square value of load current in a full wave rectifier is $${{I}_{RMS}}\,=\,\frac{{{I}_{m}}}{\sqrt{2}}$$.

Root mean square value of the output load voltage VRMS: The root mean square (RMS) value of output load voltage in a full wave rectifier is $${{V}_{RMS}}\,=\,{{I}_{RMS}}\,\times \,{{R}_{L}}\,=\,\frac{{{I}_{m}}}{\sqrt{2}}\times {{R}_{L}}$$.

Rectifier Efficiency: Rectifier efficiency is defined as the ratio of DC output power to the AC input power.

Rectifier efficiency indicates how efficiently the rectifier converts AC into DC. A high percentage of rectifier efficiency indicates a good rectifier while a low percentage of rectifier efficiency indicates an inefficient rectifier.

$$\eta \,\,\,\,=\,\,\,\,\frac{Output({{P}_{DC}})}{Input({{P}_{AC}})}$$.

The rectifier efficiency of a full wave rectifier is 81.2%. The rectifier efficiency of a full wave rectifier is twice that of the half wave rectifier. So, the full wave rectifier is more efficient than a half wave rectifier.