Power Supply Regulators Unit 2 – Shunt Voltage Regulator
UNIT 2 – SHUNT VOLTAGE REGULATOR
UNIT OBJECTIVE
At the completion of this unit, you will be able to describe the operation, line regulation, and
load regulation of a shunt voltage regulator.
UNIT FUNDAMENTALS
A shunt regulator is designed to maintain a nearly constant load voltage for changes in line
(input) voltage or load resistance.
A shunt voltage regulator uses a regulating device, usually a transistor, in parallel (or in shunt)
with the circuit output.
The transistor forces more or less current through RS as a means to control the load, or output,
voltage (VO).
Transistor current is added to the load current. Total circuit current flows through RS.
The performance of a shunt regulator is determined by its ability to maintain a constant load
voltage.
Line regulation expressed as a percentage, indicates the ability to maintain a constant load
voltage for variations in circuit line (input) voltage.
Load regulation expressed as a percentage, indicates the ability to maintain a constant load
voltage for variations in circuit load resistance.