Dear Readers, Welcome to Rectifiers and Converters Interview Questions and Answers have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of Rectifiers and Converters. These Rectifiers and Converters Questions are very important for campus placement test and job interviews. As per my experience good interviewers hardly plan to ask any particular questions during your Job interview and these model questions are asked in the online technical test and interview of many IT & Non IT Industries.
The part of the equipment that converts ac into dc is called dc power supply.
A rectifier is a device which converts alternating current (or voltage) into unidirectional current (or voltage).
Peak Inverse Voltage (PIV) is the maximum possible voltage that occurs across a diode when it is reverse biased.
If the applied voltage in reverse biased condition exceeds peak inverse voltage (PIV) rating of the diode, then the diode may get damaged.
The type of supply available from half-wave rectifier is not satisfactory for general power supply. That is why it is generally not used in dc power supply.
In breakdown region, a diode has a risk of getting damaged or burnt because the magnitude of current flowing through it increases in an uncontrollable manner. That is why didoes are not operated in the breakdown region in rectifiers.
The ac component contained in the pulsating output of a rectifier is known as ripple.
Transformer utilization factor is defined as the ratio of power delivered to the load and ac rating of secondary of supply power transformer.
A full-wave rectifier with 60Hz input must have lowest ripple frequency equal to twice the input frequency i.e. 120Hz. If the ripple frequency is 60Hz, it means some diodes in the circuit are not working.
Filter is a device that converts pulsating output of rectifier into a steady dc level.
Series inductor and L-section filters cannot be used with half-wave rectifiers because operation of series inductor depends upon the current through it and needs a minimum current to flow at all times.
In capacitor input filter, the dc output is much larger and ripples are less in comparison to those in choke input filter. So, capacitor input filter is preferred to choke input filter.
Voltage regulation in case of p-filters is very poor and, therefore, p-filters are not suitable for varying loads.
R-C filters have poor voltage regulation and need adequate ventilation to dissipate the heat developed in the resistor R. Thus R-C filters are suitable only for light loads.
A resistance, called the bleeder resistance, is placed across the filter ouput, to provide flow of necessary minimum current through the choke at all time.
Bleeder resistance RB is placed in parallel with the load so as to maintain a certain minimum current through the choke, even the load resistor gets open-circuited, and improves filtering action.
The change in voltage from no-load to full-load condition is known as voltage regulation.
The magnitude of output dc voltage may vary with the variation of either the input ac voltage or the magnitude of load current. So at the output of a rectifier-filter combination a voltage stabilizer is required.