This circuit with junction field effect transistors was found in documentation from the 1980s. The transistors can be MPF102 or BF245 and details of the coils are not given in the original.
The cut-off frequency of the filter shown in the figure can be adjusted to values between...
This circuit was found in a Popular Electronics from the 90s. The components used are all common...
This circuit uses a dual floodgate MOSFET not very easy to obtain today. Its handling is very...