This reinforcing stages from a 1960s documentation. No information is given about the transformer and the transistor admits equivalents.
We found this circuit in Radio Electronics magazine. It triggers a load (relay) by the noise from...
We found this circuit in documentation from Ferranti from 1968. The circuit uses transistors from that...
This circuit was obtained in a 1976 magazine. We can use the 555 and another BC548 to generate square...