This circuit is from a 1964 Electronic Design. The sensor is an LDR and the transistors are general-purpose types. The circuit triggers when the light that falls on the sensor is cut off.
This circuit was found in a 1980 publication. It can be assembled with any equivalent MOSFET and...
This circuit was obtained in an American publication of 1977. The circuit generates rectangular...
We found this circuit in an English publication in 1982, but it can still be easily assembled by...