Freeze Alarm (CB14454E)

The circuit of a 1968 publication can be implemented with more modern transistors such as BC548 for NPN and BC558 for PNP.

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...