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.
JFET This configuration, quite common in this section, was found in a 90s American documentation. The...
This circuit is from a 1968 Electronic Design. The characteristics of the output transformer are not...
This circuit is from an old documentation from 1995, but it can be easily assembled today by the...