This is article will help you through the process of 12 V DC power supply. First of all this is very easy and a basic part of electronics so any one can make it.
we should start with the components that we will need and what they performing.
Transformer:-
you need a transformer of 15 V, I've chose 15 V to have some margin you can use any value in between 12 and 18 V. Transformer will step down the AC voltage that is 220 V to 15 V.
Diodes or Rectifier bridge:-
The next thing we need is a rectifier bridge, which is used to convert the AC voltage from the transformer to DC. But the voltage after the rectifier is not completely DC. It will have ripples. we can also use diodes to make rectifier bridge as I've used.
Capacitor:-
Next is Capacitor a.k.a Smoothing capacitor it will eliminate the ripples depending upon the value of capacitor which i'll tell later in this article. And i'll update the formula for finding the capacitance as soon as i recall it.
LM 7812:-
The next thing is Voltage regulator. In this case we will use LM 7812 a voltage regulator of output +12 V. It is basically a transistor.
COMPONENTS:-
#Names #Label #Value
Transformer T 15 V, 1 A
Diodes D1, D2, D3, D4 3A
Capacitor C 2200uF, 35 V
Voltage regulator U LM 7812
Above is the circuit diagram of the power supply.
If you want to make it Variable you can use Potentiometer after the Voltage regultor. But for that you should use LM 317 because with LM 7812 Potentiometer act as a load and the current rating of the supply will be disturbed.
