This circuit is from a 1980s Motorola documentation. The circuit makes use of old components that can in some cases be exchanged for modern equivalents.
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...