1 ELECTRICAL TECHNOLOGY EET 103/4  Define and explain sine wave, frequency, amplitude, phase angle, complex number  Define, analyze and calculate impedance, inductance, phase shifting  Explain and calculate active power, reactive power, power factor  Define, explain, and analyze Ohm’s law, KCL, KVL, Source Transformation, Thevenin theorem.

2 (CHAPTER 15) SERIES AND PARALLEL AC CIRCUITS

Parallel ac Networks  In a parallel ac network the total impedance or admittance is determined, then the source current is determined by Ohm’s law: where;

Parallel ac Networks where; and; By Ohm’s law;

Parallel ac Networks Power to the network; where  T is the phase difference between E and I. By Kircchoff’s current law;

Parallel ac Networks R-LR-L Time domain: Phasor (frequency) domain:

Parallel ac Networks R-LR-L

8 R-LR-L

9 R-LR-L

Parallel ac Networks R-LR-L Admittance diagram;

Parallel ac Networks R-LR-L

Parallel ac Networks R-LR-L (KCL)

Parallel ac Networks R-LR-L Phasor diagram; Power;

Parallel ac Networks R-LR-L Power factor;

Parallel ac Networks R-CR-C Time domain: Phasor (frequency) domain:

Parallel ac Networks R-CR-C

Parallel ac Networks R-CR-C Admittance diagram;

Parallel ac Networks R-CR-C

Parallel ac Networks R-CR-C

Parallel ac Networks R-CR-C

Parallel ac Networks R-CR-C (KCL)

Parallel ac Networks R-CR-C Phasor diagram;

Parallel ac Networks R-CR-C Waveform;

Parallel ac Networks R-CR-C Power factor; Power;

Current Divider Rule The basic format for the current divider rule in ac circuits is exactly the same as that for dc circuits; that is, for two parallel branches with impedances Z 1 and Z 2 :

Current Divider Rule Example Using current divider rule, find the current through each branch:

Current Divider Rule Example – solution

Current Divider Rule Example – solution (cont’d) By current divider rule;

Current Divider Rule Example – solution (cont’d) By current divider rule;