DIY Hideout: How to make a Dual Voltage Power Supply using 7812 & 7912

In this post, I will show you how to make a Dual Voltage Power Supply using 7812 and 7912

If you prefer video mode or like to watch the working of the circuit please click here to watch it on YouTube

Parts List

1 * Center Tap Transformer 240V to 15-0-15 volt 1A
4 * 1N4001 Diode
2 * 2200uF/25v Electrolytic Capacitor
2 * 10uF/25v Electrolytic Capacitor
1 * 3.3k Resistor
1 * Red Led
2 * Heat Sink
1 * 7812
1 * 7912

Theory

For this Dual Power Supply project, I am using a center tap transformer so that we get two secondary voltages. The Two-wire side of the transformer is for the incoming AC power supply & the three-wire side of the transformer is the secondary voltage side.

Important Note: For the desired voltage of +12 and -12V always use the transformer with secondary voltage rating of 15-0-15 Volts

Note: The center pin or the wire of the secondary voltage side is the GND.

The Four Diodes 1N4007 acts as the Bridge Rectifier which converts the AC voltage to the DC Voltage.

The Capacitor C1 & C2 acts as the smoothing capacitor which smooths out any fluctuations in the signal.

Next coming to the two main components 7812 and 7912 which are the two voltage regulators. The 7812 is the positive voltage regulator with current up to 1Amp and 7912 is the negative voltage regulator with current up to 1Amp.

Circuit Diagram