This circuit takes advantage of the noise generated at the reverse biased junction of a germanium diode. Other types of diodes can be used. The signal is weak.
This circuit was suggested by Analog Devices in 1980s documentation. The circuit has a grounded...
Sound waves applied to the printed circuit board corrosion tank can speed up the process. The idea...
In the figure we have the circuit of a multi-range ammeter using a 50 uA full-scale instrument. The...