Quote Originally Posted by sirvo View Post
Hello..

i developed an application (12f629) to turn on or off my car using the alarm control. To stabilize the voltage i've used the 7805 regulator. I've used 4 relays in this project. It is draining at most 250mA when the 4 relays are on. This situation of 250mA draining can occur for 40seconds and no more than that. Is it normal for the 7805 to get hot? Should I use a heat sink?

ps.. i can let my finger on it when it's full loaded.

thanks...

Sylvio
Hi, what if you kkep relay coils on unregulated voltage and release the burden from 7805?
Sarma