POWER SUPPLIES 1

Question 1

is needed for
continuous operation of many
circuits and devices in a system

Answer 1

Electrical Power

Question 2

The function of an electronic
power supply unit is

Answer 2

Convert Ac or Dc power line into the required dc voltage

Question 3

base of an electronic power supply

Answer 3

Rectifier Circuit

Question 4

This power supply contains a rectifier and a filter circuit

Answer 4

An ordinary or unregulated d.c.

Question 5

TRUE OR FALSE
In a well designed power supply, the full
load voltage is only slightly less than no
load voltage i.e. voltage regulation
approaches zero.

Answer 5

TRUE

Question 6

Also called Voltage Regulation because it
indicates the change in output voltage
due to the change in load current.

Answer 6

Load Regulation

Question 7

Indicates the change in output voltage
due to the change in input voltage

Answer 7

Line Regulation

Question 8

The change of load connected to a
power supply varies the load current
and hence the d.c. output voltage.

Answer 8

Minimum Load Resistance

Question 9

It is given by the ratio of change in load
voltage to the corresponding change in
load current

Answer 9

Output Impedance/ Internal Impedance

Question 10

A d.c. power supply which maintains the
output voltage constant irrespective of a.c. mains fluctuations or load variations is
known as

Answer 10

Regulated DC power supply

Question 11

Regulated dc power supply is made up of:

Answer 11

ordinary power supply and voltage
regulating device

Question 12

CIRCUIT OF A REGULATED POWER SUPPLY
The typical regulated power supply is a
combination of three circuits, which are:

Answer 12

1. Bridge Rectifier
2. Capacitor Filter
3. Zener Voltage Regulator.

Question 13

converts the
transformer secondary a.c. voltage (point
P) into pulsating dc voltage (point Q).

Answer 13

Bridge Rectifier / Rectifier

Question 14

reduces the pulsations in the rectifier d.c. output voltage (point R)

Answer 14

Capacitor Filter/ Filter

Question 15

reduces the variations in the filtered output voltage

Answer 15

Zener Voltage Regulator/ Regulator

Question 16

contain a number of discrete and/or integrated active devices

This is better than the Simple Zener Regulator

Answer 16

Practical Voltage Regulators

Question 17

Parts of an Electronic Power Supply

Answer 17

1. Power Transformer
2. Diode Rectifier Circuit
3. Filter Circuit
4. Regulator

Question 18

to step down the AC line voltage (230 V, 50 Hz) to about the desired AC voltage

Answer 18

Power Transformer

Question 19

to convert ac voltage from the
transformer secondary into a
pulsating dc voltage

Answer 19

Rectifier Circuit

Question 20

smoothens out the pulsating dc voltage

Answer 20

Filter Circuit

Question 21

maintains a constant
output voltage regardless of
variations in ac line voltage or the
current required by the load or both

Answer 21

Regulator

Question 22

comprises electronic devices and circuits which require the regulated DC voltage. Hence the name ‘Electronic Power Supply’

Answer 22

Load

Question 23

It is somewhat a _______ as the circuit described does not supply the power, but rather converts it from one form (ac) to another (dc)

Answer 23

Misnomer

Question 24

If the second coil has fewer turns than the
first, the device is called a

Answer 24

Step Down Transformer

Question 25

This means that a____________ will produce a secondary voltage that is larger than the primary

Answer 25

a step-up transformer