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.
This radio version with a transistor for a crystal phone was found in a Japanese magazine from...
In this circuit of Texas Instruments an incandescent lamp is used as a light source, and lenses are...
This source whose voltage depends only on the zener diode used, can supply currents up to about 3 A....