Hi guys. Been a while, I know. **broken link removed**
I'm building a test-box for a small switch panel that runs on 28vdc and I want to AND two to four inputs so that the output is source voltage (the aforementioned 28vdc) to drive a lamp.
Were this device powered by 5vdc, I'd already have the tester together, using a couple quad-AND IC chips. **broken link removed**
I wanted to do this with diode logic for simplicity's sake, but ran into a roadblock for two reasons-- up to now I have been using negative logic, and I don't want to create too much of a current draw during the "off" phase.
I thought maybe a couple diodes coupled with a FET might do the trick, but frankly, it's been something like twenty years since I did any kind of engineering with a transistor and I'm feeling a little overwhelmed by it. **broken link removed**
Can anyone help me?