We found this circuit in the April 1982 Radio Electronics magazine. It contains a good power stage whose transistor must be mounted on a good heat sink.
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...