This circuit works on analog I/O ports and was suggested by an Electronic Design from the 90s. It can be used to work as a shield in projects with microcontrollers.
Radio Electronics magazine published in a 90's issue this simple alarm that can use any general...
This circuit is from the 2005 Linear Technology Application Manual. The circuit must be powered by 5...
We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the...