Found in a 1967 General Electric documentation, this meter uses Nixie tubes, popular at a time when LED and liquid crystal displays did not yet exist.
This circuit was obtained from an American publication of 1982, but can be easily assembled today...
This circuit was found in a 90's Electronic Design. The circuit can be adapted to use modern...
This 80's circuit uses a microcontroller programmed to generate various songs. The circuit can serve...