This circuit was found in an American publication from 1968. The transistors are from the time, but it can be made from modern transistors.
The circuit shown in the figure was found in a 1974 publication. The field effect transistor may...
I found this circuit in an English publication from 1989. This configuration can be mounted with...
We found this circuit in a small espionage manual from 1993. The components are current, and the...