Found in a 1964 Electronic Design, this circuit makes use of FETs of the time. These transistors can be replaced by modern general-purpose types. The input resistance is 30 M.
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
This circuit was found in documentation from the 90s, using components from that time. The...
This circuit, obtained from old documentation, allows the recovery of sulfated batteries. The...