This 4-tube circuit was found in an American publication from 1947. It is intended for audio distribution lines using a transformer source.
We find this circuit in an American 1980s documentation. The unijunction transistor may be the...
This circuit generates a pulse of duration determined by the capacitor when an object interrupts the...
This circuit, published in 1978, has an interesting function. In the 2 V test position, the...