We found this circuit in the May 1996 Electronics Now magazine. The relay must have a voltage according to the circuit power supply and a trigger current of no more than 50 mA.
Originally designed to analyze the shape of light pulses from a flash for photographic...
This RCA circuit has current limitation. The circuit is from an ancient American documentation making...
This useful power supply was found in an 1985 Italian publication, but can still be assembled...