Using a 4046 PLL, which is not very common nowadays, this circuit was found in the October 1994 issue of Electronics Now magazine. The power is provided by the transistor and is small in this case.
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...