This circuit synchronized by the power grid can be used as a shield. We found it in an 80's Electronic Engineering. R1 can typically be 4k7.
This circuit from the 70's used germanium transistors and operated in the range of medium and...
The figure shows how to convert a rectangular signal into a triangular signal using an integrator. The...
This circuit was found in a National Semiconductor manual from the 1970s, appearing in articles and on...