This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz to 100 kHz and modern equivalent components can be used. The circuit is from Ferranti.
With this circuit it is possible to vary the resistance by adjusting the mark/space reaction of...
This sensitive circuit detects the live pole of a power grid or outlet. The circuit makes use of a high...
In the figure we have the way to connect 6 solar cells in order to obtain higher voltage and...