Module 26201- Alternating Current

The average voltage value in a circuit with a peak voltage of 170v is ________

a. 108v

Meters used in AC circuits indicate the ______ value

d. effective

In unlike-wound transformers, the primary and secondary voltages are ______

d. in phase

a transformer has 200 turns in the primary, 150 turns in the secondary, and 120vac applied to the primary. the voltage across the secondary is _______

a. 90v

a transformer with a primary of 400 turns and a secondary of 300 turns has a ______

b. step-down turns ratio of 4:3

the sine of 0 degrees is_____

b. 0

if the frequency of an AC circuit is 15 cycles per ¼ second, the hertz rating of the circuit is ______

c. 60Hz

in AC circuits containing only resistance, ______

a. all DC rules and laws apply, including Ohm's law and Kirchhoff's law.

in an AC circuit containing resistance only, ______ will flow if the resistance is 10 ohms and the voltage is 120v

b. 12A

inductance _______

b. opposes any change in circuit current

When the coil turns are increased, the _____

a. induced voltage is increased

in a transformer, ______

b. electromagnetic induction occurs

a transformer with 100 turns in its primary and 10 turns in its secondary is a _____ transformer

a. step-down

in an inductive circuit, the current at 180 degrees is _____

c. zero

unless otherwise noted, the calculations in AC circuits use _____ values

d. rms

the secondary of a CT under load should not be opened because of _____

a. induced high voltage

the self-induced voltage across an inductance L is produced by a change in current with respect to _____

a. time

if the area of the plates of a capacitor is increased, the amount of capacitance _____

a. increases

the total capacitance of a 20-microfarad capacitor in parallel with a 10-microfarad capacitor is ______ microfarads

c. 30

the phase relationship between voltage and current in a capacitive circuit is _____

b. current leads voltage by 90 degrees

when frequency decreases, capacitive resistance _______

a. increases

the peak to peak voltage in a circuit with an rms voltage of 120VAC is _____

d. 340v

if the time for one cycle is 0.1 second, the frequency is _____

d. 10

the power triangle shows that the _____ power is greater than the ______ power

c. apparent; true

the formula for inductive reactance is ______

d.