The purpose of this circuit is to cut off the high voltage when the bias voltage fails. The circuit is from a 1975 documentation and can be adapted for other purposes.
Found in a publication for radio amateurs from the 1990s, this circuit makes it possible to...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
This simple transistorized receiver with earphone was found in a Japanese publication from the...