This 6W amplifier with 4 tubes was indicated in an American documentation from 1947 to operate with recorders. The circuit uses a source with a transformer.
The four gates of a 40111 IC are used in thes two-out circuit. The output chages their state in a...
This circuit was found in a 1980 publication. It uses only 3 easily obtainable transistors. It is a...
This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old...