Download Rectifiers - SJGC Kurnool College

Dr. N.Lalitha Kumari
Lecturer in Physics
Silver Jubilee Govt. College (A)
Kurnool
The Rectifier converts the a.c. input
voltage to a pulsating d.c. output
voltage.
There are two types of rectifiers
1)Half wave rectifier
2)Full wave Rectifier
Diodes in Rectifier Circuits
Half Wave Rectifier
When a single diode is used in a
rectifier circuit, current will flow
through the circuit only during one
half of the input a.c. voltage cycle.
For this reason this rectifier is
called half wave rectifier. The
output of the rectifier circuit is
pulsating D.C
Vi = Vm Sin Wt
 During the positive half cycle diode is forward
biased.
 Therefore current IL flows through the load
resistance RL
 In forward bias voltage drop across the diode is
very small.
 In Si 0.3 V and Ge 0.7 V
 For practical purpose diode is assumed ideal so the
voltage drop is zero
 During negative half cycle diode is reverse biased
 Therefore the diode does not conduct. Hence IL is
zero
Performance of Half-wave Rectifier
:
Total RMS Value
RMS Value of AC Components :
Note that this is a general result. Now, for
Half-wave Rectifier :
Full-wave Rectifier
(Centre-tap)
PERFORMANCE OF FULL WAVE RECTIFIER
How much is its period in terms of ωt ?
Its period is , and not 2.
FORMULAE FOR ZENER REGULATOR
 RS establishes the bias current
ZM
ZENER DIODE AS VOLTAGE REGULATOR
REGULATED POWER SUPPLY
 Most of the devices in electronic equipments require
essentially a constant d.c. voltage for their operation.
 The circuit of the electronic equipment that converts
a.c line voltage of mains supply into d.c. voltage is
called Power Suppply.
 In unregulated power supply the d.c. terminal voltage
is affected significantly by the amount of current
drawn. As the loade draws more current , d.c.voltage
decreases.
 In regulated power supply d.c. voltage remains
constant and does not depend on the amount of
current drawn
Power Supply Block Diagram