James Mackey Fundamentals of Power Supplies. James Mackey RectifierFilterRegulator AC Input AC...
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Transcript of James Mackey Fundamentals of Power Supplies. James Mackey RectifierFilterRegulator AC Input AC...
James Mackey
Fundamentals of Power Supplies
James Mackey
Rectifier Filter Regulator
AC Input
AC Rectified
(Pulsating DC)
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
•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
Types of Rectifiers
James Mackey
Full-Wave Rectifier
AC Input
Diode B
Diode A
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
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.
Full-Wave Rectifiers
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