In this fire alarm circuit, a thermistor works as the heat sensor. When temperature increases, its resistance decreases, and vice versa. At normal temperature, the resistance of the Thermistor (TH1) ...

Designing an analog circuit can be a frustrating experience, as noted by Nick Cornford in his Design Idea (DI), “DIY RTD for a DMM.” With a fortnight’s struggle, I completed the design of 4 mA to 20mA ...