# Rectifier viva interview questions with answers

**What is a Rectifier?**

A rectifier is a device which converts AC (Alternating current) to DC (Direct current).

**Name the basic types of rectifiers?**

Half wave rectifier, Full wave center tap rectifier and Full wave bridge rectifier.

**What is the difference between Half Wave and Full Wave Rectifier?**

A half wave rectifier converts only half of the AC cycle to Uni-direction. Whereas a full wave rectifier converts both half cycles.

**What is efficiency of a rectifier?**

The ratio of DC output power to the applied AC input power is known as the efficiency of a rectifier.

**What is the maximum efficiency (η) of a half wave and full wave rectifier?**

Half wave rectifier – 40.6% and full wave rectifier – 81.2%.

**What is form factor?**

It is the ratio of the RMS value to the Average value.

**What is peak factor?**

The ratio of maximum value to the RMS value.

**What is called ripple Voltage?**

Ripple voltage in a rectifier output is the amount of AC content present in the output DC, it causes periodic pulsating of the DC voltage which is derived from the AC source.

**Define Ripple factor in rectifiers?**

Ripple factor is the ratio of root mean square (RMS) value of the AC component or ripple voltage to the average value of rectified DC output.

A half wave rectifier has a Ripple factor value greater than that of a full wave rectifier.

**What is the importance of PIV voltage of a Diode in A Rectifier Circuit?**

PIV (Peak Inverse Voltage) is the maximum possible voltage that a diode can withstand in the reverse bias. When a voltage greater than peak inverse voltage is applied across the diode, an avalanche breakdown occurs which cause permanent damage of the diode. Hence, the PIV of the diode should be always greater than the maximum reverse voltage.

**What is the PIV of full wave center tapped rectifier and why?**

A center tapped full wave rectifier has a PIV of two times the maximum voltage, 2Vmax. Because in a center tap rectifier the voltage across the two half winding becomes 2Vmax, which is the total voltage across the two end terminals of the winding (The maximum voltage across the load will be always half of the maximum total winding voltage, which is the voltage between one end terminal and center tap).

**What is the Transformer utilization factor in rectifiers?**

The Transformer utilization factor (TUF) of a rectifier circuit is defined as the ratio of the DC power available to the load to the VA rating of the secondary coil of a transformer.

**What is the TUF of a half wave rectifier?**

TUF of a half wave rectifier, 0.2865.

**What is the advantage of a bridge rectifier over a center tapped full wave rectifier?**

A center tapped transformer is not required for a bridge rectifier.

The output voltage of a Bridge rectifier is twice than that of the center tap rectifier for the same secondary winding of a transformer.

PIV of a bridge rectifier is half of the center tap rectifier for the same output voltage.

A bridge rectifier utilizes full voltage of the transformer secondary whereas a center tap rectifier utilizes only of the secondary voltage.

A bridge rectifier has a TUF of 81.2% and a center tap has only 67.2%.

**Test your knowledge : Rectifier – Quick Assessment Test**

Why half wave rectifiers are not preferred?

Half wave convert only one have cycle of the voltage

Because in half wave rectifier more AC component will come with dc at the load in one word efficiency means capability of the half wave rectifier is low to convert ac to dc so, thats why it is not prefered

Because it gave high value of ripple factor

😁😁

As its name says, a half wave rectifier utilizes only half of its input and the remaining 50 % which is the negative half cycle of the Alternating Current is unused. That is no output during the period of the negative half cycle. Hence it cannot deliver a satisfactory power supply for general applications.

In order to use a load with a half wave rectifier, we need to use a filter capacitor of high capacitance. So it would not discharge the output voltage below a minimum value before the next positive half cycle begins. But using with a larger capacitor it draws more current in the once half cycle.Hence half rectifiers are only useful with simple circuits like LED lights, a few milli ampere loads, etc.

Thank you it is really helpful thing 😊😊😊😊😁😁😁

these are good questions on rectifier.

they are really good questions on rectifiers

Tganks so much for being open with your knowledge