This stereo circuit is from Japanese 1960 documentation. The circuit was originally designed to work with a tube amplifier, removing power from it. The transistors are germanium.
Found in a 1964 Electronic Design, this circuit shows how to modulate a signal with a dynamic low...
This circuit is from an 80's documentation, firing when the input voltage exceeds 5 V. The SCR can...
The transistor used is one of the first power Darlingtons with a collector current of 3 A. The...