Switching 12 volts

Forum 2005-2010 (read only) Hardware Interfacing
1

I need to simulate the tachometer output of my motorcycle for testing. It's a nominal 12v square wave running up to 120hz. The load is a voltage divider bringing the voltage back down below 5v - total of 32K to ground.

I've cobbled up the circuit below from various googlings - does it look workable? I understand the logic will be inverted, that's no problem.

2

I don't know...I wouldn't be comfortable with letting the 5V source sink current from 12V. Could be bad. I'd recommend something more like this:

3

great - thank you very much.