De La Salle University - Dasmariñas

ECE 22

Macaspac, John Joselle V. ECE22 Part 2
1. A resistance of 20 W and a coil of
inductance 31.8 mH and negligible resistance
are connected in parallel across 230 V, 50 Hz
supply. Find (i) The line current (ii) power
factor and (iii) The power consumed by the
circuit.
2. Two impedances Z1 = (150 + j157) ohm
and Z2 = (100 + j 110) ohm are connected in
parallel across a 220-V, 50-Hz supply. Find
the total current and its power factor.
3. Two impedances (14 + j5) Ω and (18 + j10)
Ω are connected in parallel across a 200-V,
50-Hz supply. Determine (a) the admittance
of each branch and of the entire circuit; (b)
the total current, power, and power factor and
(c) the capacitance which when connected in
parallel with the original circuit will make the
resultant power factor unity.