Transcript No Slide Title

Fundamentals of Power Supplies
James Mackey
Rectifier
AC
Input
Filter
AC
Rectified
(Pulsating DC)
Regulator
Smoothed
DC
Smoothed
&
Regulated
DC
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James Mackey
Basic Diode Circuits
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Capacitive Filtering
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Finite Charge/Discharge times of RC circuit smooths out
pulsating DC from the Rectifying circuit
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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
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Diode A
Full-Wave
Rectifier
Diode B
AC Input
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Output waveform
from Diode A - half
wave rectified + cycle
Output waveform
from Diode B - half
wave rectified - cycle
Combined waveform
from both + & - cycles
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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.
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Full-Wave Bridge Rectifier
+
+
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Full-Wave Rectifier and Filter Circuit
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Full-Wave Bridge Rectifier and Filter Circuit
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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.
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Scale is mA
Scale is A
James Mackey
James Mackey