EETC Circuit Theory 5

Question 1

In a delta-connected three-phase load, the relationship between line current and phase current is:

Accepted Answer

IL = √3 × IP

Answer

In a delta connection, IL = √3 × IP because each line carries the phasor sum of two phase currents displaced by 60°.

Question 2

The bandwidth (BW) of a series resonant circuit is related to its Q-factor and resonant frequency (f₀) by:

Accepted Answer

BW = f₀ / Q

Answer

Bandwidth BW = f₀/Q; a higher Q-factor produces a narrower bandwidth and sharper selectivity.

Question 3

When two inductors are magnetically coupled with a mutual inductance M, the total inductance when connected series-aiding is:

Accepted Answer

L1 + L2 + 2M

Answer

For series-aiding coupled inductors, LT = L1 + L2 + 2M, because the mutual inductance adds to both coils.

Question 4

A wattmeter in an AC circuit measures:

Accepted Answer

True (real) power (W)

Answer

A wattmeter measures true (real) power in watts, which accounts for the phase angle between voltage and current.

Question 5

Applying mesh analysis, a mesh current is assumed to flow:

Accepted Answer

Around a closed loop (mesh) in one direction

Answer

In mesh analysis, a mesh current is assigned to each independent closed loop (mesh) and is assumed to circulate around that loop.

(EETC) Electrical Technician Certification Practice Test