The selected circuit was found in GE's 1977 semiconductor manual. 3N84 is a controlled silicon switch and SCRs support equivalents. The transistor can be a BC558, depending on the supply voltage.
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...