Completed the project, but not working right
OK, might need a bit more help here. I totally benched tested the circuit board and it worked OK. I have exactly 3.3v as the referance. I inputed approx 2.7v and it did not trigger. I then applied about 4.3 V and it triggered. My problem now is that when it is all installed in my car, the coil is "hot", or "on". If all is right, the coil should not be triggering until it gets its 5V signal. Here is one possibility. I measured the input referance voltage in my car, and it was not 2.5V at idle, it was 1.9V....In further testing, I am getting a reading 7.3V on the TIP31 Collector to Coil (Pin 85). Now if the output of the TIP31 "is" triggered, shouldnt that be 12-13V? Why am I getting 7.3V.........and why am I getting "any" voltage at all if it isnt supposed to be triggered until the car gets to 5V +/-?? What could I be missing? What is the typical voltage for an automotive 12V relay at the coil in order to trigger it? Would 7.3V be enough to turn the relay on.
Maybe I have a bad relay.........cause it kind of hums a little.
Thanks for the help.
OK, might need a bit more help here. I totally benched tested the circuit board and it worked OK. I have exactly 3.3v as the referance. I inputed approx 2.7v and it did not trigger. I then applied about 4.3 V and it triggered. My problem now is that when it is all installed in my car, the coil is "hot", or "on". If all is right, the coil should not be triggering until it gets its 5V signal. Here is one possibility. I measured the input referance voltage in my car, and it was not 2.5V at idle, it was 1.9V....In further testing, I am getting a reading 7.3V on the TIP31 Collector to Coil (Pin 85). Now if the output of the TIP31 "is" triggered, shouldnt that be 12-13V? Why am I getting 7.3V.........and why am I getting "any" voltage at all if it isnt supposed to be triggered until the car gets to 5V +/-?? What could I be missing? What is the typical voltage for an automotive 12V relay at the coil in order to trigger it? Would 7.3V be enough to turn the relay on.
Maybe I have a bad relay.........cause it kind of hums a little.
Thanks for the help.