This circuit uses a 555 (according to the diagram) to generate 50 ms tone bursts at a frequency of 1.5 kHz. The circuit is from an 80's Electronic Design.
This sensitive circuit detects the live pole of a power grid or outlet. The circuit makes use of a high...
This FET stage circuit was obtained from old American documentation but can be applied to any FET....
Found in old American documentation, this circuit can use crystals between 27.5 and 33 MHz...