Found in a 1967 American electronics magazine, this circuit has an input impedance of 2000 ohms. The circuit can be built with modern equivalent transistors.
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...