This is a different circuit for a component from the past, the zirconium arc lamp used in projectors. The circuit is from an August 1972 Radio Electronics magazine.
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...