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7912 as negative voltage regulator issue


Guest Kaash

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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

post-101596-14279144561538_thumb.jpg

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Why didn't you look at the datasheet for the 7912??
It shows an input capacitor and an output capacitor that prevent it from oscillating at a high frequency which causes heating.

The voltage from its input to output TIMES its load current sets how much dissipation (heating) it makes when the capacitors are there.

Is it mounted on a finned heatsink with thermal grease? That is how to cool it.

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  • 1 month later...

Hee, hee.
I did not notice that the supply polarity was backwards.

Lol what amused me is he wasted 5 regulators without realising there was a problem with the circuit.

The lesson is, if it gets hot and components smoke, check there's nothing wrong with the circuit before replacing them and trying again.

Here's how to do it correctly.

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  • 6 years later...
On 8/17/2013 at 1:39 AM, Guest Kaash said:

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

post-101596-14279144561538_thumb.jpg

Hi

please confirm connection probe

becauce your connection same like voltage regulator 78.. 

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