Found in a 1980s American documentation, this circuit can use a SCR and a general-purpose transistor. R2 is 1 M and R1 is 10k. The capacitor is 47 uF.
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...