Deck 3: Common Diode Applications: Basic Power Supply Circuits

Question 1

https://d2lvgg3v3hfg70.cloudfront.net/TB2838/. For the transformer shown, which current and voltage have the greatest values?

A) IP and VP
B) IS and VS
C) IP and VS
D) IS and VP

Answer 1

IP and VS

Question 2

A positive full-wave rectifier has a secondary voltage of 20 Vpk. The peak load voltage for the circuit is

A) 20 Vpk.
B) 9.3 Vpk.
C) 19.3 Vpk.
D) 10 Vpk.

Answer 2

9.3 Vpk.

Question 3

A rectifier is used to

A) convert ac to pulsating dc.
B) reduce the variations in a pulsating dc signal.
C) maintain a constant power supply dc output voltage.
D) convert one dc level to another.

Answer 3

convert ac to pulsating dc.

Question 4

The term leaky is used to describe a capacitor that is

A) partially open.
B) partially shorted.
C) too high in value.
D) too low in value.

Question 5

The term full load means

A) load resistance has increased to its maximum value.
B) load resistance has decreased to its minimum value.
C) the load is disconnected from the circuit.
D) load current has decreased to its minimum value.

Question 6

When testing a basic power supply, you see that the primary fuse is blown. This typically indicates that

A) a short exists somewhere in the power supply.
B) an open exists somewhere in the power supply.
C) the fuse itself is the most likely cause of the circuit failure.
D) Any of the above conditions could exist.

Question 7

A filtered half-wave rectifier has a peak secondary voltage of 20 Vpk. The PIV rating for any diode in the circuit must be at least

A) 20 V.
B) 30 V.
C) 10 V.
D) 40 V.

Question 8

A half-wave rectifier is connected to a transformer with a secondary voltage of 20 Vpk. The average output voltage is

A) 19.3 Vdc.
B) 13.7 Vdc.
C) 6.14 Vdc.
D) 12.3 Vdc.

Question 9

Why is the bridge rectifier used more commonly than the full-wave rectifier?

A) It does not require the use of a center-tapped transformer.
B) With equal input voltages, the bridge rectifier provides a higher dc output voltage.
C) The bridge rectifier can be directly coupled to an ac line input.
D) All of the above.

Question 10

What is the total current that is being drawn through RS in Figure ?

A) 6.06 mA
B) 3.3 mA
C) 2.76 mA
D) 2.15 mA

Question 11

Which of the following will reduce the ripple in the output from a filtered rectifier?

A) Increasing the value of the filter capacitor.
B) Increasing the load resistance.
C) Adding a zener voltage regulator.
D) All of the above.

Question 12

A 22 μF filter capacitor is connected to a half-wave rectifier. If the value of the capacitor is increased to 100 μF, the ripple in the circuit output will

A) increase.
B) decrease.
C) remain the same.

Question 13

The basic power supply is made up of

A) a regulator, a follower, and a rectifier.
B) a filter, a follower, and a regulator.
C) a rectifier, a filter, and a regulator.

Question 14

The most commonly used type of rectifier is the

A) half-wave rectifier.
B) full-wave rectifier.
C) bridge rectifier.

Question 15

A full-wave rectifier has a 9.3 Vpk output and a 4.7 kΩ load resistance. What is the dc load current for the circuit?

A) 1.26 mA
B) 2.61 mA
C) 629.8 μA
D) 1.4 mA

Question 16

A voltage regulator

A) maintains a constant power supply dc output voltage.
B) steps up or steps down the line voltage.
C) reduces the variations in ac line voltage.
D) Both A and C above.

Question 17

A negative half-wave rectifier eliminates the alternations of the transformer output.

A) positive
B) negative

Question 18

In the schematic for a half-wave rectifier , the diode points toward the ungrounded side of the load. The output from the rectifier is

A) positive.
B) negative.
C) either positive or negative, depending on the polarity of the transformer secondary voltage.

Question 19

A bridge rectifier has values of V1 = 120 Vac, turns ratio = 5:1, and RL = 500 Ω. What is the dc output voltage?

A) 14.4 Vdc
B) 7.19 Vdc
C) 20.8 Vdc
D) 22.6 Vdc

Question 20

When troubleshooting a rectifier, it is important to check every diode in the rectifier.

Question 21

If you replace the 100 Ω resistor with a 400 Ω resistor, the output voltage for the circuit will be

A) 6.4 V.
B) 6.08 V.
C) 6 V.
D) 5.6 V.

Question 22

A transformer with a 10:1 turns ratio has a 120 Vac line input. The transformer secondary is connected to a half-wave rectifier circuit using a capacitor filter. Ignoring any ripple, what is the dc output voltage from the circuit?

A) 16.3 V
B) 10.4 V
C) 5.7 V
D) 3.6 V

Question 23

Which transformer could be used for the sole purpose of providing electrical isolation between a power supply and its ac line input?

A) A
B) B
C) C
D) none of the above

Question 24

What is the value of IZ for the circuit?

A) 40 mA
B) 38 mA
C) 20 mA
D) 2 mA

Question 25

What is the value of the load voltage for the circuit?

A) 6.4 V
B) 6 V
C) 5.6 V
D) None of the above.

Question 26

What is the dc load voltage?

A) 33.2 V
B) 16.3 V
C) 11.3 V
D) None of the above.

Question 27

Identify the power supply circuits represented in Figure .

A) A= transformer, B= rectifier, C= regulator, D= filter
B) A= transformer, B= regulator, C= filter, D= rectifier
C) A= filter, B= transformer, C= rectifier, D= regulator
D) A= transformer, B= rectifier, C = filter, D= regulator

Question 28

What is the value of the circuitʹs secondary voltage?

A) 24 Vac
B) 33.9 Vp
C) 67.8 Vpp
D) All of the above.

Question 29

What is the ripple voltage across the load?

A) 0.25 V
B) 0.126 V
C) 121 mV
D) 76 mV

Question 30

What is the value of the load current?

A) 14.1 mA
B) 7.1 mA
C) 6.8 mA
D) 4.3 mA