View Full Version : 7805 regulator heatsink

01-23-2005, 02:37 AM
I am building a highly compact bot. I have a 9V source, and I am driving a microcontroller with the help of ua7805 regulator. The controller drives two stepper motors (9V source) through two ULN2003s. My question is how essential is it to solder the regulator along with the heat sink? (As excluding it will really help me maintaining its compactness)

01-23-2005, 03:38 AM
missed one tiny detail, the 9v source is a 9v battery.. is that feasible for the above load??

01-23-2005, 12:34 PM
Since your 7805 shall drive only the microcontroller the current drawn would be very less and it wont heat up.
and since the source voltage is also 9v, (drop is only 4V)
Hence there is no need of heatsink in this case.

01-24-2005, 12:21 AM
hi this is pallav(pallav_engg@yahoo.com)

you can avoid heat sink if the current output taken from the regulator is less than 100mA

if load is more than that ,than inspite of using a external heatsink (like aluminium,etc) use a PCB integrated heat sink. On the pcb provide lagest(possible) copper area an connect it to the regulator tab.

hope this will help you.

01-02-2006, 11:33 PM
experts suggest to solder it in tat way....
it is really needed..
steppers draws a lot of current and u need to cool the regulator if u want it to work fine... else it might blow up{has happened with me}...

so do use a heat sink..