Low battery indicator 555 (CB9551E)

This circuit can operate with different voltages, depending on the zener used. We found it in a 90s American documentation.

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...