Making a temperature regulator

There are a lot of options for temperature sensing - everything from PN junctions (diode voltage), to various IC sensors, to thermocouples, RTDs, thermistors, etc. What you choose will highly depend on the application.

There's a pretty good technical reference on Omega Engineering's website:

For sensing high temperatures, you'll need a thermocouple. Depending on the peak expected temperature, you could either use a K-type thermocouple, or one of the more esoteric higher temp ones, like an R-type T/C. These are good for fairly precise sensing of temperatures in this range.

For very precise sensing of low temperatures (30-40C) your best bet is an RTD (Resistive Temperature Device). This will give you accuracy of within a couple of tenths of a degree.

For either of the two applications, you'll need something called a temperature controller. This is a programmable device which accepts the sensor input, and has an output which controls the heat treating furnace or the incubator.

Also, your heat treating furnace will probably need a ramp-soak feature, which makes the furnace temp rise at a timed, set rate to go from one temp to a second higher one (ramp), then maintains that temp for another set period of time (soak).

A good one-stop source of information on temperature control is the Omega Engineering Temperature Handbook. Not only is there a lot of technical information, but also a wide variety of products available which will do the job for you. Best of all, the Temperature catalog is free. That's free, as in beer. Don't believe it, take a look:

Click "Free Literature" on the menu bar at the top of the webpage, then select Omega Product Handbooks (the Temperature handbook is the thick red one).

A lot of the technical information is available in abbreviated form on the website. Just click around and have fun.

Good luck Chris

I've sent off for that free info from Omega and it should be a start to this. I liked that idea for the heat treat oven of having it so goes from one temp to another. That would really help Ken

for the kiln a thermocouple is probably the way to go

for temps below boiling point there are semiconductor sensors like LM335 that give a nice simple voltage output.

feed the output into a comparator that also sees a correclty adjusted reference volttage and then into whhatever control device you want to use... (optocoupler to a triac, or a transistor to drive a relay.)

you'll probably be wanting a fan in that incubator to keep the temperature even.

Bye. Jasen