This circuit was found in an American publication from 1968. The transistors are from the time, but it can be made from modern transistors.
This double tone generator uses a specific integrated circuit, having been found in a 1977 CMOS...
This circuit is used to test PNP or NPN transistors giving the status indication through LEDs. The...
This dimmer for incandescent lamps was obtained from an American 1990s documentation. The circuit...