The circuit is from 1968, but we can use a modern one like the 741. The symmetrical power supply voltage (two batteries or source) can be from 9 to 12 V.
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...