Suggested for the control of photographic enlargers, this 1967 General Electric circuit uses still common components. The circuit directly controls a lamp for exposing negatives.
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...