This circuit that we found in a 1990 documentation uses an LED as a sensor. The operational amplifier is equivalent to the 741 and the trigger adjustment is made in the potentiometer.
We found this circuit with a Q factor of 25 in the Linear Applications Handbook by National...
Found in a 1967 Electronics World, this preamplifier uses an integrated circuit from that time,...
This circuit uses a special 1950's RCA strobe tube. It can be built with equivalent components for the rest...