This simple general-purpose transistor mixer was taken from an article in Electronics Now magazine in March 1994. You can choose a low-noise transistor such as the BC549.
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...