This circuit was found in a 1970 IEEE publication. The circuit functions as a voltage controlled variable resistor and can be used with audio signals. Transistors admit current equivalents.
This circuit enables the bilateral command of triacs with the use of low current switches. The...
This circuit emits a sound when a magnetic field, of a magnet, for example, approaches the sensor....
It can be obtained from Mouser Electronics, sensors (receivers) transmitters and benders for...