This circuit is from a 1964 Electronic Design book that presents application ideas for transistors. The circuit uses a transistor from that time, but modern equivalents can be used.
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...