Chapter 6 _ALTERNATING CURRENT.pdf - A H C 6 R E PT PAA...

PAA 20204
ALTERNATING CURRENT
PHYSICS II
CHAPTER 6

CONTENT
6.1 Alternating Voltage and
Currents
6.2 Resistor in AC Circuits
6.3 Capacitor in AC circuits
6.4 Inductors in AC Circuits
6.5 RLC Circuits
LEARNING
OUTCOMES
Solve resonance problem in RLC circuit.
At the end of this lesson students should be able to:
Define frequency, period, amplitude. calculate peak
current and voltage, power and root mean square current
and voltage.
Write an equation of current and voltage at any time.
Know phase relation between current and voltage for ideal
components, RC, RL and RLC circuits.
Calculate impedance and phase angle for RC,RL and RLC
circuits.

Alternating Current (AC) and Direct Current (DC) are both describe types of current flow
in a circuit .
In Direct current , the electric charge (current) only flows in one direction .
Electric charge in Alternating Current , on the other hand, changes direction
periodically.
The voltage in AC circuits also periodically reverses because the current changes
direction with same frequency.
ALTERNATING CURRENT (AC)
Electric charge (current) only flows in
one direction.
Is an electrical current varies sinusoidal in
magnitude reverse.
its direction periodically with same frequency .
Direct Current (DC)
Alternating Current (AC)

An Alternating urrent (AC) is describes the flow of current
that changes direction periodically.
•AC is used to deliver power to houses, office buildings, etc.

Square waves are often
used in digital and
switching electronics to
test their operation.
The most common type of
AC is the sine wave. The AC
in most homes and offices
have an oscillating voltage
that produces a sine wave.
AC can come in a number of forms, as long as the voltage and current are
alternating. If we plot its voltage overtime,we might see a number of different
waveforms.
Triangle waves are found in
sound synthesis and are useful
for testing linear electronics
like amplifiers
Sine Wave
Square Wave Triangle Wave

The number of
complete cycle in one
cycle
The variation of current along
the path from ABCDE
The time ( in second)
taken to complete one
cycle
The maximum value of
current at point B and D
ALTERNATING CURRENT
One cycle
Period
Frequency
Peak value

EQUATION OF ALTERNATING CURRENT AND
ALTERNATING VOLTAGE
The sinusoidal voltage can be produced by rotating
a coil with a constant angular velocity in a
uniform magnetic field.
All function encountered in electrical engineering is produce in sinusoidal
alternating.
Sinusoidal
VOLTAGE can be
expressed by:
Sinusoidal CURRENT can be
expressed by:

A phasor is an arrow whose length represents the
amplitude of an AC voltage or current.
The phasor rotates counterclockwise about the origin
with the angular frequency of the AC quantity.
Phasor diagrams are useful in solving complex AC
circuits.
Resistor Capacitor
Inductor
Phasor Diagrams