The sensors in this circuit that triggers when the temperature goes out of a certain range are common diodes. The circuit is from the 1991 Reista Electronics Experimenter's Handbook.
Suggested by Motorola documentation from the 1980s, this circuit makes use of MOSFETs of the time....
In the figure we have a small general-purpose amplifier with the LM386 integrated circuit and...
This circuit allows you to use a digital multimeter as a thermometer. The sensor is mounted in a...