This experimental circuit with Nixie tube was found in the Radio Electronics magazine of March 1969. The circuit serves for demonstrations and also for testing these digital indicator tubes.
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....