ASVAB ASVAB Electronics Fundamentals and Circuits 4

Question 1

A transformer has a primary winding of 200 turns and a secondary winding of 50 turns. If the primary voltage is 120V, what is the secondary voltage?

Accepted Answer

30V

Answer

The turns ratio is 200:50 = 4:1, so secondary voltage = 120V ÷ 4 = 30V.

Question 2

Which type of capacitor is polarized and must be installed with correct polarity?

Accepted Answer

Electrolytic capacitor

Answer

Electrolytic capacitors are polarized due to their oxide layer construction and will be damaged if installed backwards.

Question 3

In a purely inductive AC circuit, the current lags the voltage by how many degrees?

Accepted Answer

90°

Answer

In a purely inductive circuit, the inductor causes current to lag the applied voltage by exactly 90 degrees.

Question 4

What does a diode's 'forward voltage drop' refer to?

Accepted Answer

The minimum voltage required for the diode to conduct in the forward direction

Answer

Forward voltage drop is the minimum voltage across a forward-biased diode needed for it to conduct; typically ~0.7V for silicon.

Question 5

Two capacitors of 4μF and 12μF are connected in series. What is the total capacitance?

Accepted Answer

3μF

Answer

Series capacitance: 1/C = 1/4 + 1/12 = 3/12 + 1/12 = 4/12, so C = 12/4 = 3μF.

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