I'm trying to design a schematic that will be on when one temperature A is higher than temperature B, and will turn off when A reaches B or is below. I need the output to drive a 12V relay; I was thinking some LM34's hooked to a LM393, but not sure where to go from here. I know I'm probably gonna need an op-amp to raise the output of the comparator. I wouldn't mind being able to adjust the difference between the two before the relay is activated; for instance, change it from temperature A being 10* higher will turn it on, but then the next day I could adjust it so 30* will allow it to turn on. I imagine a pot would allow this, but I'm not quite sure how the ouput is from the LM34s. TIA everyone
I'm trying to design a schematic that will be on when one temperature A is higher than temperature B, and will turn on when A reaches B or is below. I need the output to drive a 12V relay; I was thinking some LM34's hooked to a LM393, but not sure where to go from here.
Ranges are gonna vary; I'm using it to control a solenoid for an intercooler sprayer on my car. Temperature B will be the ambient air temperature, and Temperature A will be the intercooler temperature. Ambient air varies from 10*F to 95*F here in FL, and the intercooler temp will vary from 0*F to 130*F
Ranges are gonna vary; I'm using it to control a solenoid for an intercooler sprayer on my car. Temperature B will be the ambient air temperature, and Temperature A will be the intercooler temperature. Ambient air varies from 10*F to 95*F here in FL, and the intercooler temp will vary from 0*F to 130*F
hi,
I am drawing a circuit, do you really means this... will be onwhen one temperature A is higher than temperature B, and will turn on when A reaches B or is below. ??
hi,
I am drawing a circuit, do you really means this... will be onwhen one temperature A is higher than temperature B, and will turn on when A reaches B or is below. ??
Thanks! I have a few questions though: I can't seem to locate resistors 3, 5, and 6, or transistor 1 in your schematic. Is R2 to simulate the solenoid, or do I need it in series with the solenoid? Also, u2 is from the 393 comparator, correct? Sorry, I haven't done any schematics in years
Thanks! I have a few questions though: I can't seem to locate resistors 3, 5, and 6, or transistor 1 in your schematic. Is R2 to simulate the solenoid, or do I need it in series with the solenoid? Also, u2 is from the 393 comparator, correct? Sorry, I haven't done any schematics in years
OK, thanks. I just ordered everything. I made a few small changes (just master on/off rocker, and a push-button to bypass the temperature sensors in case I want it on when the temps aren't in the range), but will let you know how it works. Thanks for the help!
OK, thanks. I just ordered everything. I made a few small changes (just master on/off rocker, and a push-button to bypass the temperature sensors in case I want it on when the temps aren't in the range), but will let you know how it works. Thanks for the help!
Yes, pretty sure I understand it. The V-out goes to the 10K resistor and then the comparator. Vs and ground go to power and ground, respectively. Also, I purchased LM35's instead. The schematic, shouldn't change any, right? My understanding was the only difference is the scale being used; LM34 is Fahrenheit, while LM35 is Celsius
Yes, pretty sure I understand it. The V-out goes to the 10K resistor and then the comparator. Vs and ground go to power and ground, respectively. Also, I purchased LM35's instead. The schematic, shouldn't change any, right? My understanding was the only difference is the scale being used; LM34 is Fahrenheit, while LM35 is Celsius
lol, the only reason I picked them over the LM34's is the site I bought everything from only has the LM35's in stock. I'd much rather buy everything from one place, and since they operate the same and I won't actually be reading the temperature, I didn't see a problem. And thanks for the filter schematic. They will be remote from the circuit, so no telling if I'll need that or not. Hopefully I won't, but inside an engine bay, I have a feeling I might