Transistor Inverter - when does excessive small wattage become a problem?

Thread Starter


Joined Jul 12, 2016
A high side switch is preferred because you want the ground on the chip to be at ground, rather than the several 100 mV that the NPN would drop.
I don't think 800mV (which is what a typical transistor drops at most) will be enough to turn the radio module on.

Also, using a PNP will allow you to drive the base simply through a resistor since there is no issue with drawing current when the output is high
I already built my circuit on PCB before asking this question and I don't want to redo my circuit all because someone prefers PNP.

I'd rather waste milliseconds drawing lots of current to get the module successfully programmed then to spend days redoing my circuit (PCB exposure/etching/hole-drilling, part sourcing, soldering etc.)

The entire circuit wont stay on forever. I might have it powered for maybe 10 minutes maximum at a time.


Joined Jun 5, 2013
You completely misunderstand how a high side switch works, and my entire post pointing out why it is preferred. If you don’t want to learn anything, why are you bothering to continue with this thread?