I want to thank everyone that helped my with the level and flow sensor problems. I was trying to use Radio Shack phototransistor/IRLED pairs
- part # 276-0142. I couldn't get any of the circuits to... work reliably. It was very frustrating, trying to diagnose what I had done wrong. Then yesterday, I stuck one of the phototransistors on a curve tracer. It was worthless. OK, maybe I fried it, hooked it up backwards or something. Tried one I had opened but not hooked up in a circuit - again worthless. I had a technician open a NEW package and test the pt. Worthless. Maybe these would make resistors, and not good ones, but they do NOT function as transistors or phototransistors. I bought some Vishay units from Mouser and tried them out today. The circuits now work the way they should. *sigh* Rat Shack is close and convenient, but full of worthless semiconductors. I've got to do a little more planing to order parts instead of just running down the street, but buying reliable parts will make life easier. Again, thanks for your help, and thanks for listening to my rant