Schematic illustrating how an open-loop shunt voltage regulator works.
The schematic is a resistive voltage divider circuit consisting of a battery and two resistors connected in a single loop with a breakdown diode across the resistor representing the load.
The battery, which is the left branch, represents the power source and is marked V in.
R 1 and R 2 form a voltage divider producing the voltage V o which represents the output voltage.
The current flowing in the loop circuit is marked I.
R 2, which is the right branch, represents the load.
Across R 1 is a breakdown diode which acts as a shunt regulator shunt. R 1, a variable resistor which connects the left and right branches, represents the series regulator function and is varied to obtain the desired output voltage V o.
Original: 03 June 1999, revised 05 June 1999