This circuit is from a 1969 General Electric manual. The SCR may be the TIC106. Similar circuits from other sources are found on this website.
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...