This circuit was found in a Popular Electronics from the 90s. It is based on components still common today and an optical coupler for the triac. The sensor is a thermistor.
Bipolar transistors are types of general use like BC548, while the power MOSFET can be of any type...
We found this circuit in an old documentation. Its purpose is to turn on warning lights when the...
This simple humidity alarm circuit includes a timed warning oscillator whose time is set to R4....