Download No Slide Title

Fundamentals of Power Supplies
James Mackey
Rectifier
AC
Input
Filter
AC
Rectified
(Pulsating DC)
Regulator
Smoothed
DC
Smoothed
&
Regulated
DC
James Mackey
James Mackey
Basic Diode Circuits
James Mackey
Capacitive Filtering
James Mackey
Finite Charge/Discharge times of RC circuit smooths out
pulsating DC from the Rectifying circuit
James Mackey
Types of Rectifiers
•The effect of a single diode rectifying circuit - called
a half-wave rectifier - produces the 60 Hz pulsating
DC signal that must be smoothed by the filter circuit.
•The action of this circuit removes 1/2 of the AC
component from the Power Supply input and
increases the difficulty of smoothing.
•The full-wave rectifier saves both halves of the AC
input and makes the signal easier to smooth by the
filter circuit
James Mackey
Diode A
Full-Wave
Rectifier
Diode B
AC Input
James Mackey
Output waveform
from Diode A - half
wave rectified + cycle
Output waveform
from Diode B - half
wave rectified - cycle
Combined waveform
from both + & - cycles
James Mackey
Full-Wave Rectifiers
The full-wave rectifier circuit requires a center
tapped transformer in order to function.
Transformers are usually the most expensive
part of a power supply; with center tapped
transformers more expensive than single
transformers.
For these reasons, an alternate full-wave
circuit is usually used, called a full-wave bridge
rectifier.
James Mackey
Full-Wave Bridge Rectifier
+
+
James Mackey
Full-Wave Rectifier and Filter Circuit
James Mackey
Full-Wave Bridge Rectifier and Filter Circuit
James Mackey
The operation of all of these circuits is based
on the rectifying property of semiconductor
diodes.
We saw these effects in the Workbench
exercise done earlier.
A plot of diode voltage versus diode current is
shown on the next slide.
James Mackey
Scale is mA
Scale is A
James Mackey
James Mackey