This is a very common circuit in the days of xenon flashes for cameras. This is from a Radio Electronics magazine from November 1965. It uses an SCR and has manual triggering.
We find this circuit in an American 80's documentation. It makes use of IC sensor which is mounted...
This is a configuration obtained from an old manual, using an operational amplifier of the time....
In the figure we have the way to add hysteresis to an operational amplifier. The relationship...