This circuit was found in a documentation of the 80s, having didactic purpose. For R1 values between 10k to 1M can be used. Transistors are general purpose types.
This clipper or limiter circuit limits the amplitude of AM or FM audio signals. The diodes are...
The varactor or varicap diode tunes the signal for listening to SSB signals on a common receiver. The...
This circuit is based entirely on SCRs. The circuit is from an American 80's documentation; and the PUTs...