This circuit amplifies signals from 0.5 Hz to 300 kHz. We found it in an old documentation. Equivalent transistors may be used. The gain is 20 dB.
This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old...
Found with variations on this site, this circuit was taken from an American documentation from the...
This brightness control for incandescent lamps or engine speed has been found in a 1970 English...