This circuit was found in an English magazine from 1977. Signal inputs and outputs must be shielded, and the circuit can be powered by battery, since its consumption is low.
This circuit was obtained in a 1975 documentation. The maximum frequency depends on the diodes and the...
In the figure we have the basic configuration of an operational amplifier for AC signals using the...
This traditional signal injector from a 1970s publication uses germanium transistors. We can mount it...