This circuit with LDR and neon lamp has its operating frequency given by the light. The circuit is from a Radio Electronics from July 1963. It can be used for teaching or experimental purposes. C1 can be changed according to the desired frequency.

This circuit with LDR and neon lamp has its operating frequency given by the light. The circuit is from a Radio Electronics from July 1963. It can be used for teaching or experimental purposes. C1 can be changed according to the desired frequency.