AC Circuit Basics

"AC" current refers to _____

• current that changes or alternates its direction

• current that is always in one constant direction

• all calculataions for voltage in a circuit

• none of the provided answers are correct

Answer explanation

AC is an abreviation for Alternating Current. This refers to current that changes its direction.

Common household AC power from a wall outlet _____

• has a voltage rated at 120 V(RMS)

• has an RMS voltage of about 70% of the Peak Voltage

• all answers are wrong!

• is rated at 120 volts Peak to Peak

Answer explanation

The best answer is that both A and B are true.

A generator can create electric current _____

• when its coils of wire are moving inside a magnetic field

• that has a sinusoidal waveform

• that has an arbitrary waveform

• by maintaining no motion between the wires and the magnetic field inside

Answer explanation

The best answer is that both A and B are true.

Watt's law can be written as P = I x V, where _____

• P is power, I is current and V is voltage

• this same equation applies to AC and DC values

• 
• this equation is not the same for AC as for DC

With pure resistor circuits, Voltage and Current are in phase _____

• but with pure capacitor circuits or pure inductor circuits, they are not in phase

• with DC circuits but not ever in phase with AC circuits

• with AC circuits but not ever in phase with DC circuits

• No Correct answers

Three phases of AC current, equally spaced apart _____

• are 90 degrees out o phase with each other

• are 120 degrees out of phase with each other

• are 150 degrees out of phase with each other

• none of the answers provided are true

The following is a common AC power source: _____

• 120 VAC, 1 phase with 3 wires

• 208 VAC, 3 phase, with 5 wires

• 480 VAC, 3 phase, with 4 wires

• all answers are correct

A stepdown transformer has _____

• a smaller voltage at the primary windings

• a smaller voltage at the secondary windings

• P secondary > P primary

• steps down current while increasing voltage

Three phase transformers can have _____

• Wye and Delta windings

• only Wye winidngs

• only Delta windings

• only Step Up winding configurations

The turns ratio indicates _____

• the ratio of the power at the Primary to the Secondary

• the ratio of the voltage at the Primary to the Secondary

• the efficiency of the transformer

• the number of times the stator spins internally