Using components of the time, this 3 and half digit scale was found in an Electronics Now from the 90s. The circuit is powered by a 9 V battery.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
I found this circuit in an Electronics Handbook from 1989. The circuit can be assembled with a...
This circuit makes use of a 2N301 germanium power transistor. We found it in a documentation from...