This circuit for a frequency of 40 kHz was found in an old Electronic Design. There were no constructive data for the transformer used in the output.
This circuit uses old germanium transistors because it was found in an old magazine from 1973....
This logic level indicator also indicates the presence of pulsating signals through a third LED. It...
This circuit is from the 1990 Motorola Linear Databook, which can be developed with more modern...