This oscillator for frequencies up to a few tens of kilohertz was found in a 1970s documentation. The transistor can be of general use. For the component values used, the frequency is 250 Hz.
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...