Good adfternoon. I'm working on my smoker, my COVID project, and I've got it looking like a time machine. Digital thermometers everywhere and a PID controller. But I need help with one last project. However, my electronics background is limited. I made crystal radios when I was a kid and I took tube theory in college. So I know enough to hurt myself and burn up a few ICs. Here's my project. My smoker has a pilot light which is kept on by a thermocouple. The pilot light is buried in the bowels of the smoker. The only way that I know that it's on is by watching the temperature increase, I can't see the pilot light. I want to make a circuit that will light an LED when the pilot light is on. The gas valve solenoid holding voltage is about 6 millivolts and it releases at about 3 millivolts. Max voltage output of the thermocouple is about 32 millivolts. The gas valve is a White-Rodgers 36C03. I'd like the LED to go on and off at about 8 millivolts. My smoker has a regulated 12 VDC power supply (LM7812). It powers the digital thermometers. I've been looking at voltage sensor circuits. I'm thinking that I could compare the output of a 12 volt powered 50k ohm/20 ohm voltage divider with the output of the thermocouple. From what I see in the literature, an LM741 won't work. I'd need to amplify the millivolts to volts. Could I use an LM358 for that? Or, maybe, could I use an LM358 for the whole thing? Or anything else? If any of you have a moment of boredom that you'd like to spend on helping me with this project it would be much appreciated.
Thanks.
SmokerinCB
Thanks.
SmokerinCB