1. AC CIRCUIT ANALYSIS
Introduction
SEE 1003 Section 08
Nik Din Muhamad

2. PHASOR DIAGRAM
A phasor diagram is a diagram illustrating how the various phasors in a particular situation relate to one another. The diagram is simply a pictorial way of viewing the voltages and currents.

3. PHASOR CONCEPT 1
A series RLC in the Figure below has the voltages across each element as follows:
|VR| =50 V
|VL| =50 V
|VC| =100 V
(i) What is the magnitude of Vs
(ii) Determine R, L and C if the current flow in the circuit is 20. R L Vs
f =100 Hz C

4. PHASOR CONCEPT 2
A parallel RLC in the Figure below has the currents through each element as follows:
|IR| =7.5 A
|IL| =10 A
|IC| = 15 A
(i) What is the magnitude of Is
(ii) Determine R, L and C if the voltage across the parallel elements is V =1000 V. + V - Is
f = 50 Hz C R L

5. PHASOR CONCEPT 3
A series RL is connected to a 240 V ac source. If the voltage across the resistor is 150 V, find the voltage across the inductor.

6. PHASOR CONCEPT 4
What value of w will cause Vo to be zero. Determine magnitude of the voltage across capacitor for that frequency. + Vo -
2 W
5 mF
50 cos wt
20 mH

7. PHASOR CONCEPT 5
What magnitude of Ic will cause VS in phase with IS. Determine value of the capacitor C. IS IC
IRL IC
VS = 240 V
f = 50 Hz VS
IRL= 560