ISCET Power Supply Circuits and Voltage Regulation

Question 1

What is the primary purpose of a filter capacitor placed after a rectifier in a DC power supply?

Accepted Answer

To smooth the pulsating DC output by reducing ripple

Answer

To increase the ripple frequency

Answer

To step up the DC output voltage

Answer

To limit the peak output current

Question 2

A half-wave rectifier is connected to a 120V RMS transformer secondary. What is the approximate average DC output voltage (ignoring diode drop)?

Accepted Answer

54V

Answer

120V

Answer

84.8V

Answer

170V

Question 3

In a full-wave bridge rectifier, how many diodes conduct simultaneously during each half-cycle of the AC input?

Accepted Answer

Two

Answer

One

Answer

Three

Answer

Four

Question 4

The ripple factor (r) of a power supply filter is best described as:

Accepted Answer

The ratio of RMS ripple voltage to average DC output voltage

Answer

The ratio of peak output voltage to average output voltage

Answer

The percentage of input AC that appears at the output

Answer

The ratio of output current to input current

Question 5

A 7812 three-terminal linear voltage regulator produces which regulated output voltage?

Accepted Answer

12V

Answer

5V

Answer

8V

Answer

15V

Question 6

What is the minimum PIV (Peak Inverse Voltage) rating required for diodes in a full-wave bridge rectifier with a 24V RMS transformer secondary?

Accepted Answer

33.94V

Answer

16.97V

Answer

24V

Answer

48V

Question 7

Which type of voltage regulator uses a zener diode connected in parallel with the load as its primary regulation element?

Accepted Answer

Shunt regulator

Answer

Series pass regulator

Answer

Switching regulator

Answer

Buck-boost regulator