7912 as negative voltage regulator issue

[Kaash]

hi guys..
im using 7912 as negative voltage regulator but when i connected it with 12v or 20v supply it got very hot without any output voltage.
i wasted 4-5 regulators but get no output -12, is there other any way to connect it?
help plz.
thanks

 

[BobK]

You have the ground and power reversed. For a negative regulator the ground has to be higher than the input.

Edited: You also need the capacitors on the input and output. See the datasheet.

Bob

 

[Kaash]

will u recommend me capacitor's rating?

 

[BobK]

Look up the datasheet. It has a sample circuit.

Bob

 

[Kaash]

ok thanks