BillO:
oric_dan:
Oof, 1/2 Amp through the transistor when input held high. Nice 2.5W glow worm.Well, maybe you can show me the math on that? Vce measured at .5V in my test rig with that rascally little ole input held high. That's .25W where I live. And if you're real paranoid about it, decouple the DC with a cap on the input.
5V/10ohms = 0.5 Amp.
5V*5V/10ohms = 2.5 Watts.
Plus, it's much much worse if you're not providing enough base drive to saturate transistor.
Worst case, 1.25 watts --> transistor=poof!
Just wondering though, why would you leave the input high? Do you not have control over that in your world? Interesting. Here in Canada microcontrollers do what you tell them to. Unusual, I know, but must be a Great White North thing.
Read post #43.