This circuit was found in a 1974 publication. It consists of a voltmeter for high voltages, up to more than 100 V, using a neon lamp.
This circuit was obtained in a 90s documentation. However, it can be developed with modern...
This circuit uses a 455 kHz crystal or for close frequencies. We found it in documentation from...
This circuit turns off after a time that depends on C1. The circuit is from an Electronics Now...