Originally indicated as an alarm alert in a 1990s US publication, this circuit can be used as a shield to control a strobe lamp. The sensor is a optocoupler with LDR.
This transistor tester with different gain ranges was found in documentation from the 1980s. The...
We found this circuit in a 1997 documentation. It can drive sets of LEDs or lamps through SCRs in...
This circuit of a 1964 Electronic Design uses a photodiode from the time. Modern equivalent can be used....