Basic Concepts:-
1. The voltage across an impedance is v(t) = 100(200t + 15) and the current is i(t) = 4sin(200t – 15).
Determine p(t) , P , Q and S and the power factor.
2. Give the units of Real, Reactive , Apparent and Complex power.
3. Inductors _____ VARs . (absorbs/ deliver).
4. Capacitors _____ VARs . (absorbs/ deliver).
5. What is the peak voltage of a voltage source which has an RMS value of 25V?
6. Let P = 8K, Q = 10K, draw the power triangle. What is the value of apparent power?
7. Let us suppose in a communication system the signal source has an impedance of 2+3j, the
transmission line has an impedance of 0.2 + 0.5j. To allow maximum power transfer from signal
source to load what should be the impedance of the load?
8. Suppose the current through an impedance 3+3j is 5<30 mA. (Note the current is not RMS
value). What is the value of the real and reactive power dissipated across the load? Also find
power factor, reactive factor, apparent power and the value of power angle.
9. The voltage across a capacitor of 5uF is 45cos(2000t+50). Determine the reactive power.
10. In a balanced 3-phase Wye-Wye configuration, what is the value of the current flowing through
the neutral terminal?
11. What is meant by a balanced three phase voltage supply, what is the value of the sum of all the
three voltages?
12. If a balanced 3-Phase Wye load has an impedance of 4+2j, draw the equivalent Delta load.
docsity.com
