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.
Measuring capacitances and resistance this simple instrument was found in Radio Electronics...
The LM143 integrated circuit is a high voltage operational amplifier from National Semiconductor that is...
We found this circuit in the November 1985 issue of Radio Electronics magazine. It uses TTL...