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.
16 commercial test circuit for tubes and transistors appeared in Radio Electronics magazine in...
Suggested by an American publication, this circuit has 5 operating conditions indicated in the...
This circuit with an integrated circuit of the time was found in the magazine Radio Electronics of April...