7806 warm up

I built a power supply with a 7806 voltage regulator, the transformer provides 12V and the capacitor is 2200uF. The regulator is warmed up. I have measured the voltage in capacitor and this is 15V. Why does the 7806 warm up? why does the voltage in capacitor is to high?

Thanks.

Posted by Diego (diego_r1@hotmail.com) on 29/06/2005, at 01:53 GMT

Warm up

Diego The voltage at the capacitor will charge to the peak voltage of the AC waveform.
The peak voltage of an AC waveform will be
1.414 X 12 Volts = 16.968V WITH NO LOAD
Also with an unloaded transformer the output voltage is most likely to be higher than the rated output voltage. The reason for this is that a transformer is manufactured to be used at some RATED current the resistance of the wire has to be taken into account and at higher currents more voltage will be lost in this resistance so an UNLOADED transformer will have a higher output voltage.
The reason the 7806 is getting warm??
How much current are you drawing?
If you are not drawing any current make sure that it is connected correctly.

Best of luck

Wal

Posted by Wal Douglas on 14/09/2005, at 17:41 GMT