This circuit is from a documentation from the 70s. The circuit uses logic gates of the time, which in many cases were arrays of transistors allowing use as audio amplifiers, as in this case.
With this circuit it is possible to add a conductance scale to a common multimeter. The circuit was...
With a touch of S1 this circuit keeps a small strand of nichrome warm enough to light a cigarette....
Mouser Electronics has in stock the MUSBR robust connectors for USB 30 applications from Amphenol. These...