This circuit was found in a 1966 EEE. What it does is it converts the logic levels of 0 V and +4 V into -6 V and +6 V. Some older type transistors can be replaced by modern equivalents.
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...