I want to power my microconroller with a little tactile button. The chip itself should only draw a few mA, but the LEDs will draw quite a bit more. If I design my circuit like this will I have to worry about it draining my battery while the switch is open? Will the pulldown resistor on the NPN prevent leakage when the uC is powered off? I haven't got resistor values yet but I figure it will be around 10 times of whatever the base resistor ends up being.

Thanks

 

Best guess-- a μA or 2 leakage.

 

I think I can live with that.... Thanks

 

Why not switch the +9V to the uC and the LED's then it's not a problem?

 

Because the tactile buttons are usually only rated for 50 -100mA. All of mine are anyway.