This circuit is from the time when cars used contact breakers. This 80's version measures the dwell angle of the contact breaker for dwell adjustment using an era integrated circuit, the LM3917.
I found this circuit in a documentation about thyristors from the 70s. The circuit uses a diac...
We found this audio amplifier stage with 500 ohms of input impedance in an old American...
In the presented receiver, from a 1964 documentation, a transistor is used as a detector,...