I've been doing something in testing and throw-away project which is, I know, bad - or at least incorrect. But it's been working really well, and I thought I'd get some feedback on the practice.
I've got a good number of FETs that I've taken off of motherboards - ridiculously low Rds, even at low voltages - Vgs threshold around 1.5v, and < 10milliohm with a Vgs of 4.5v. And when you can get 10, 15, or 20 at a time, they're certainly a good find.
The practice is that I've been connecting the AVR output pin directly to the base without anything in between. I know that a resistor should be used, for current limiting - or at least to prevent ringing. But things have been working quite well.
The AVRs haven't self-destructed or (seemingly) been damaged by the brief in/outrush of current, and for simple PWM dimming, I dunno if I'd see any external effects from the ringing or not. Unfortunately, I do not have access to a scope, or I'd take a look at what's going on directly.
So... just how bad (or not-so-bad) is this?