This circuit was found in a PE Hobbyst Handbook of 1989. It uses a black light fluorescent of the time. Small fluorescent black light from 1 to 4 W can be used.
Found in a 1969 documentation, this circuit consists of a multi-oscillator with neon lamps....
This high-performance circuit was found in the 1982 SGS Linear Integrated Circuits Manual. The...
We have in the diagram another way to make the null adjustment of an operational amplifier. In...