This circuit was found in an American 1990s documentation. It can directly trigger a triac when light is detected by the sensor. The integrated circuit is common, like the 741.
This beat frequency oscillator or BFO was found in an American 1980s documentation. The circuit is...
Currents of a few milliamps are enough to drive loads up to 500 mA with this circuit. The...
This circuit was obtained in the 1994 National Linear Application Handbook. The circuit admits other...