This simple circuit for a common 110 V power grid was found in a 1980s American documentation. The circuit uses neon lamps as indicators.
This portable transceiver circuit for the 11 meter or 27 MHz band was found in a 1991...
This circuit was found in an American 1980s documentation. It makes use of an unusual MOSFET today...
This circuit was found in an old Linear Technology documentation. The working principle can be...