I am building a 12v power supply based on this.
Main changes are use of two 2,200uF filter caps instead of one, and 7812 (12v) regulator instead of 7809. Plugged it in the first time and the voltage regulator went up in smoke before I noticed and unplugged it.
Having now replaced it, it still gets very hot very quickly after being plugged in, but I can't see what I have done wrong with the wiring. Voltage straight off the rectifier is about 17v. With the rest of the circuit connected, voltage on pin 1 (input) of the regulator reads about 11v, and the output around 1v. Within a couple of seconds the regulator is too hot to touch.
First thought was that regulator pinout was wrong, but it is 7812 - pin 1 v(in), pin 2 ground, pin 3 v(out).
Any ideas what would cause behaviour like this?
This is a picture of my implementation:
The terminals 1 & 2 are the input rail, terminals 3, 4, 5 & 6 are output - the copper bar (and outer two terminals) is the negative rail. The regulator connects the three - Pin 1 in, pin 2 negative, pin 3 out.