This circuit was obtained in a documentation from the 80's. However, using TTL it is still modern, being able to be used as Shields for microcontrollers or part of digital projects.
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...