42 kHz oscillator (CB21805E)

This circuit was used as an eraser for old tape recorders. The circuit is from a 1960 Mullard transistor manual.

Signal Tracer with MW Radio (CB20509)
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
Flip Flop Toggle (CB24436E)
This circuit was found in documentation from the 90s, using components from that time. The...
Battery Desulfator Charger (CB19386E)
This circuit, obtained from old documentation, allows the recovery of sulfated batteries. The...