The original purpose of this circuit, which we find in old American documentation, is to modulate an RF carrier for telecommunications applications. Transistors support equivalents.
This telegraph monitor was found in an American documentation for radio amateurs from the 1970s. The...
We found this circuit in a European publication from the 1970s. The transistor is made of...
This adjustable source from 2 to 15 V uses transistors from the 60's, as indicated in the...