Power Supply Regulators Unit 3 – Series Voltage Regulator
UNIT 3 – SERIES 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 series voltage-regulating circuit.
UNIT FUNDAMENTALS
A series regulator has a regulating transistor (Q1) in series with the output (circuit load RL).
Q1 is referred to as the series pass transistor because all of the load current must pass through
the transistor.
The series regulating configuration shown is also referred to as an emitter follower circuit.
In the series regulator, the voltage drop across Q1 is varied to maintain a nearly constant output
voltage.
RS, in series with Q1, reduces the power dissipation of Q1.
R1 provides the base current for Q1 and the bias current for zener diode CR1.
CR1 provides the circuit reference voltage.