AC Circuit Analysis A Revision SKEE 1023 Circuit
- Slides: 8
AC Circuit Analysis: A Revision SKEE 1023 Circuit Theory Dr. Nik Rumzi Nik Idris 1
REVISION Things you should know Things you have learned in SKEE 1023 Things I EXPECT you to know ! 1 Knows how to write expressions for sinusoidal waveforms v(t) = ? sin( t + v(t) Vm ? ) v(t) = ? cos( t + ? ) o t o 2
Revision 2 AC circuit analysis deals with phasors and impedances Phasors: A complex number containing information on amplitude and phase of a sinusoidal voltage or current A cos ( t o) A o A sin ( t o) A ( o 90 o) Impedance: A ratio between voltage and current phasors – it is a complex number but NOT a phasor Z = R + j. X You MUST know how to do deal with complex number 3
Revision Z = R + j. X 4
Revision Z = R + j. X Impedance Resistance Reactance Im Pure resistor: Z = R Re Im Re Pure capacitor: Z = Pure inductor: Z = Im Re 5
Revision Z = R + j. X Impedance Resistance Inductive impedance: Z = R + j. X Reactance |Z| X R R Capacitive impedance: Z = R - j. X |Z| -X 6
Revision 3 You must know how to draw phasor diagrams V 1 V 2 V 1 = 20 30 o V V 2 = 10 120 o V I 1 = 5 -60 o A 120 o 30 o -60 o I 1 7
Revision 4 Perform nodal and mesh analysis in frequency domain Steps involved are exactly similar to DC anaysis However in AC, we deal with complex numbers 8