Thermal cut-off

[Jeff Birkle]

Hello,
I am building a circuit and require a thermal cut-off for 20deg C but can't find any that go below 66deg C.
Do they exist?
If not, any other easy way to cut-off at that temp?

 

[Mosaic]

If you know the current at which you want to limit you can use these:
https://www.newark.com/jsp/search/b...&Ntt=electronic+fuse&Ntx=mode+matchallpartial

Otherwise you're gonna need a thermistor and a comparator (OPA) to drive a relay or control an NFET which allows power to your circuit.
https://www.vialab.org/Bioe_1310/Labs/lab_07.pdf

 

[MikeMl]

20deg C is less than room temperature. You are going to have to buy or build a thermostat like the one that controls the heating in your house.

 

[Mike odom]

There are lots of IC temperature sensors that give a calibrated output voltage per degree F (or C). Two examples are the MCP9700 (10mv/°C) from Microchip or the LM34 (10mv/°F) from Ti (or National Semi). Then either read with a micro (ADC input), or run through a comparator.

 

[crutschow]

What are you trying to control?