This circuit triggers an alarm in the event of a power failure. The circuit is from an 80's documentation, being powered by 9 V battery. The parts are common today.
This second-order filter was found in old American documentation and can be applied to other...
Found in an old Elektor, this circuit uses two 7-segment displays to indicate the volume of an...
Found in a 90s Popular Electronics, this circuit makes use of power MOSFETs. Equivalent MOSFETs can be...