Reverse polarity protection 2 (CB22140E)

This circuit has an improvement over the previous one as it also has an LED indicator for correct polarity.

Square to Triangular Converter (CB6098E)
This circuit converts square (rectangular) signals into triangular signals with typical 16 V...
FM Spy Transmitter (CB19431E)
We found this circuit in a spy book from the 90s. Transistors admit equivalents and the coil can...
Treble Booster (CB10990E)
This circuit was obtained in a 1979 English magazine. This circuit is a treble filter that,...