Quote Originally Posted by CluckShot View Post
How do we determine what the pullup should be? I mean 100 to 300 ohms or 10 K ohms doesn't exactly give me the data I need. (Does it vary with the circuit being driven for example?)
I was taught, back in the "old days", to figure for about 1 ma to flow in the pullup (or, when needed, pulldown). Thus for 5-volt TTL, 4.7K; for 12-volt CMOS logic, 10K. I still use these values without thinking, and everything still works.