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temperature controlled switch Answered

I I'm working on a water spray kit for my intercooler on my car and i want the pump to turn on when the air outside is => 50 and the intercooler is like 15-75 > then the air i want both of the them to be adjustable. I i could make it activate when its like >50 the and it activate 30 above that the out side air or something like that could and one help me out the a schematic.


Do Comparator Work like if-then statement I'm a programmer this is my first time doing this kind of thing. Any sites for part and recourse to get me started you recommend.

. An RTD is just a resistor with a decent temperature coefficient. Searching for RTD +circuit" should get you started on your inputs.
. Yeah. IF-THEN is a pretty good analogy. I'd use Boolean operators, < and >, but IF-THEN will work.
   IF input(0) > setpoint THEN output(0) = 1 ELSE output(0) = 0
. The Wikipedia link I gave earlier should get you started on comparators. Or try searching for "comparator +circuit". There are several topics on Ibles about where to get electronic parts.

But they're are many different kinds what kind to I use a 4 bit, 8 bit what? Where would I buy them form and good sites?

. Component selection will not be that critical. For your application, repeatability is more important than absolute accuracy. Ie, it's OK to be off a little bit as long as it's always off by the same amount. As long as the RTD will handle the temperature and vibration, you should be OK.
. The more I think about it, the more I believe I'd use a microprocessor, instead of comparators. Unless you know what the parameters are and don't need to do any experimenting. A uP would also allow you to add other sensors, such as, barometric pressure, humidity, engine speed, &c. If you were only monitoring one variable, a uP would be overkill.
. Four bits will not give you enough resolution. Eight bit minimum; 12, if possible; 16 is overkill. A comparator is an analog device - infinite bits.
. If I were going to do this, I'd use RTD -> A/D -> uP -> relay -> pump. Some uPs have built-in A/Ds. You can also find uPs (usually called controllers) that are designed specifically for temp control and accept RTDs directly.

I ordered book on electronics they should be hear soon. Dose the Component output the highest or lowest V that is inputted or dose it output the VCC power that is inputted