This circuit for the very low frequency range was found in the Radio Electronics magazine of February 1983. The components are according to the frequency range to be amplified.
This 1-transistor oscillator circuit was found in the March 1965 Radio Electronics magazine. The...
In the figure we have a way to adapt a phone obtained to the output of a common amplifier. The...
This sensitive touch key appears on this website from other sources. This version was taken from a...