Found in a 90s American documentation, this circuit uses an integrated from the time that is difficult to obtain today. The sensor is a common photodiode.
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....