This circuit is from a Radio Electronics magazine from August 1974. It used one of the first photomultiplier tubes that was to be powered by high voltage. The power came from the mains.
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...