This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic Circuits Volume 5 from 1995. The circuit uses components that are still common today.
In this circuit found in a Texas Instruments 2016 documentation we have an adjustment for the...
This circuit is ideal for creating a source that allows the use of automotive power devices on a...
This circuit is from an English publication of 1982. The bipolar transistor can be a BC548 and the...