Alternating Current

Question 1

On an oscilloscope what is displayed on the following axis: Horizontal, Vertical
A.
Horizontal: Amplitude
Vertical: Time
B.
Horizontal: Frequency
Vertical: Phase
C.
Horizontal: Time
Vertical: Amplitude
D.
Horizontal: Voltage
Vertical: Current

Answer 1

C.
Horizontal: Time
Vertical: Amplitude

Question 2

Calculate the peak voltage and frequency if V/Div is 2.5 and Time/Div is 5μS:
A. Peak: 5 V, Frequency: 50 kHz
B. Peak: 7.5 V, Frequency: 40 kHz
C. Peak: 10 V, Frequency: 30 kHz
D. Peak: 7.5 V, Frequency: 20 kHz

Answer 2

B. Peak: 7.5 V, Frequency: 40 kHz

Question 3

Calculate the peak voltage and frequency below if V/Div is 2mV, and Time/Div is 2mS:
A. Peak: 4 V, Frequency: 500 Hz
B. Peak: 8 V, Frequency: 100 Hz
C. Peak: 6 V, Frequency: 400 Hz
D. Peak: 6 V, Frequency: 250 Hz

Answer 3

D. Peak: 6 V, Frequency: 250 Hz

Question 4

Solve total capacitance (Ct) of five 25μF capacitors in Series.
A. 5μF
B. 10μF
C. 125μF
D. 25μF

Answer 4

A. 5μF

Question 5

Solve total capacitance (Ct) of two 100μF capacitors in Series.
A. 100μF
B. 200μF
C. 50μF
D. 25μF

Answer 5

C. 50μF

Question 6

Solve total capacitance (Ct) of three 20μF capacitors in Parallel.
A. 20μF
B. 60μF
C. 40μF
D. 80μF

Answer 6

B. 60μF

Question 7

Solve total capacitance (Ct) of four 30μF capacitors in Parallel.
A. 30μF
B. 60μF
C. 90μF
D. 120μF

Answer 7

D. 120μF

Question 8

When using an analog multimeter to check a capacitor, what would indicate a GOOD capacitor?
A. The needle quickly moves to zero resistance.
B. The needle stays steady at a high resistance.
C. The needle fluctuates without settling.
D. The needle stays at a low resistance throughout.

Answer 8

B. The needle stays steady at a high resistance.

Question 9

What rule determines the magnetic polarity of a coil/inductor?
A. “Right-hand rule”
B. “Left-hand rule”
C. “Coulomb’s law”
D. “Fleming’s law”

Answer 9

A. “Right-hand rule”

Question 10

What is the unit of measurement for inductors?
A. Ohms (Ω)
B. Farads (F)
C. Henries (H)
D. Watts (W)

Answer 10

C. Henries (H)

Question 11

What is the formula for inductors in Series and Parallel?
A.
Series: Lt = L1 x Ln
Parallel: Lt = L1 + Ln
B.
Series: 1/Lt = 1/L1 + 1/Ln
Parallel: Lt = L1 + Ln
C.
Series: Lt = L1 / Ln
Parallel: Lt = L1 x Ln
D.
Series: Lt = L1 + Ln
Parallel: 1/Lt = 1/L1 + 1/Ln

Answer 11

D.
Series: Lt = L1 + Ln
Parallel: 1/Lt = 1/L1 + 1/Ln

Question 12

In a parallel circuit, the total inductance is_____than the_____inductor.
A. Greater, Largest
B. Less, Smallest
C. Equal to, Largest
D. More, Smallest

Answer 12

B. Less, Smallest

Question 13

Infinite ohms in the secondary windings would be what kind of fault?
A. Short
B. Ground
C. Open
D. Overload

Answer 13

C. Open

Question 14

A break or open in the primary would create how many volts in the secondary?
A. 120 V
B. 0 V
C. 240 V
D. Variable volts

Answer 14

B. 0 V

Question 15

Transformer windings are 25V, 1A, and 100 turns in the primary. What would the Voltage and Current be in the secondary if there are 500 turns in the secondary?
A. Sv = 125 V, Si = 0.2 A
B. Sv = 50 V, Si = 0.5 A
C. Sv = 125 V, Si = 5 A
D. Sv = 250 V, Si = 0.4 A

Answer 15

A. Sv = 125 V, Si = 0.2 A

Question 16

Transformer windings are 70V, 50mA, and 300 turns in the primary. What would the Voltage and Turns be if the current in the secondary was 200mA?
A. Sv = 35 V, Ns = 150
B. Sv = 17.5 V, Ns = 300
C. Sv = 70 V, Ns = 600
D. Sv = 17.5 V, Ns = 75

Answer 16

D. Sv = 17.5 V, Ns = 75