Bench-Top Power Supply Construction

The purpose of the project is to build a power supply that is capable of supplying a variable voltage output from 1.5V to 12V.

The adjustable voltage regulator used is the LM317T which takes input from two resistors R1 & R2 and then ratchets the voltage accordingly. The voltage output is permitted to be controlled by this linear potentiometer R2. The power supply is protected against short circuits by the two diodes. If the input power is short circuited, D1 will protect the regulator from the capacitors discharging and if the output power is short circuited, D2 will protect the regulator from the capacitors discharging.

A smoothing capacitor is by the ceramic disk capacitor C1 while the transient response of the regulator is improved by the electrolytic capacitor C2. The use of PCB-mounted SPST switch is for turning the power ON and OFF without unplugging the wall wart. To easily connect the power supply to several different circuits and components, the PCB-mounted terminal strip is utilized. To prevent the regulator from burning itself, a suitable heat sink is used. By adjusting the values of R1 & R2, this power supply can be highly adaptable.

Rest of the project