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Design of temperature switch

Design of temperature switch

Design of temperature switch

(OP)
Hi, currently I'm in a bind. I'm trying to make a temperature switch which can be used to turn off power to an oven. As I'm on a budget, I can't go for sophisticated stuff. I measured the potential difference of a thermocouple but since it's in mV. I can't do much with it to trigger a relay. Are there any suggestions as to how to go about it? A link as to how to do it will be very helpful.

Thanks and regards

RE: Design of temperature switch

Why not simply fix the oven?  It should already come with a thermocouple switch that uses a bimetallic temperature sensor that cnotrols a gas valve.  

If not, you can certainly buy one from an oven parts supplier.  This solution requires no circuitry and no electrical power.

TTFN

RE: Design of temperature switch

(OP)
I get the point about the oven. The problem is that this so called oven doesn't have any temperature control switch. It's not really an oven but it does look like one. It's more like a barbeque pit. What I'm doing here is to sense the temperature and cut off the air supply to it, thus extinguishing the fire. The mechanical aspect of this personal project is very easy but since I'm not an electronic/electrical engineer, I have no idea of how to wire the thermocouple with so little current to a relay to cause the switching. And to enable the system to close the air vent shutters.

RE: Design of temperature switch

Nonetheless, iw would seem significantly easier to use existing commercial parts rather than trying to develop:

an amplifier circuit
a thresholding circuit
a relay driver
an air supply turnoff
power routing
power conditioning

Every single water heater, oven uses only thermomechanical parts. A water heater uses thermomechanical switches to turn on/off the gas supply.

TTFN

RE: Design of temperature switch

IRSTUFF: The bimetal is two longitudinally welded different
metal strips, which bends if temp.changes-- i.e. mechanical.

Termocouple is two different wires welded at a single point.
Heated gives a few milliV. Needs icepoint reference and amplifier.

<nbucska@pcperipherals.com>

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