Applied Electricity

1. Alternating Current
Circuits
Based on
Serway and Jewett
e6

2. CHAPTER OUTLINE
1 AC Sources
2 Resistors in an AC Circuit
3 Inductors in an AC Circuit
4 Capacitors in an AC Circuit
5 The RLC Series Circuit
6 Power in an AC Circuit
7 Resonance in a Series RLC Circuit
8 The Transformer and Power Transmission
9 Rectifiers and Filters

3. Chapter Objectives
1-Describe alternating current (AC) circuits.
2-Investigate the characteristics of simple
series circuits that contain resistors,
inductors, and capacitors and that are
driven by a sinusoidal voltage
3- The illustration of the functions of some
useful device such as transformers, power
transmission, and electrical filters will be a
conclusive end of this course.

4. 1 AC Sources

5. 2 Resistors in an AC
Circuit

6. Phasor Diagram

7. Phasor diagram, R

9. AC terminology
The average value of the
current over one cycle is zero.
But, does not matter with the
resistance, R
P=i2
R
The average value of the
instantaneous current,
The square root of the mean

10. Example
This equation states that an alternating current whose
maximum value is 2.00 A delivers to a resistor the same
power as a direct current that has a value of (0.707)(2.00 A)
= 1.41 A. Thus, the average power delivered to a resistor
that carries an alternating current is
When we speak of measuring a 120-V alternating voltage from an
electrical outlet, we are referring to an rms voltage of 120 V. A quick
calculation using Equation 33.5 shows that such an alternating voltage
has a maximum value of about 170 V.

12. 3 Inductors in an AC
Circuit

13. Phasor diagram, L
IL lags behind ∆vL

15. 4 Capacitors in an AC
Circuit

16. Phasor diagram, C

20. 5 The RLC Series
Circuit

24. 6 Power in an AC
Circuit
1/2 0
Power factor

27. 7 Resonance in a Series RLC
Circuit
A series RLC circuit is said to be in resonance
when the current has its maximum value.

29. ASSIGNMENT
1-Redraw the resonance curves, I and
P, using EXCELL software
2- Read sections 33.8 and 33.9