## Quiz sheet for parallel AC circuits

Adding another capacitor in parallel with a capacitor that is already connected in parallel with a resistor, will cause the a.c. supply current to

A) increase

B) decrease

C) lag the voltage

D) improve power factor

ANSWER: A

The impedance of a parallel a.c. circuit can be determined from the:

A) supply voltage divided by the supply current

B) phasor sum of the impedances of each branch

C) numerical sum of the branch currents

D) inverse sum of the branch currents

ANSWER: A

When drawing the currents and voltage in a phaser diagram representing a three branch AC circuit, the reference phaser is the

A) supply voltage

B) current in the first branch

C) current in any purely resistive branch

D) supply current

ANSWER: A

When using a phasor diagram to represent a parallel RLC circuit, the reference phasor would be:

A) Voltage

B) Current

C) Impedance

D) Resistance

ANSWER: A

When a parallel circuit is operating at resonance, the circuit impedance is:

A) maximum

B) minimum

C) determined by the capacitor

D) determined by inductive reactance

ANSWER: A

In a parallel a.c. circuit containing resistance, inductance and capacitance, an increase in resistance will result in:

A) an increase int the phase angle

B) a decrease in the phase angle

C) an increase in reactance

D) an increase in current

ANSWER: A

When a parallel RLC circuit is operating at resonance the supply current is:

A) minimum

B) maximum

C) half

D) 0.866 of the maximum

ANSWER: A

A parallel circuit is at resonance when the:

A) inductive reactance equals capacitive reactance

B) capacitance equals the inductance

C) resistance equals inductance

D) capacitance is equal to the inverse of the inductance

ANSWER: A

At resonance, the total circuit impedance will be equal to:

A) the line voltage divided by the line current

B) the sum of all the resistance in the circuit

C) the resistance minus the reactance

D) the sum of all resistance and reactance

ANSWER: A