This circuit was obtained in a 1969 Mullard manual. The transistors are from that time. The input sensitivity is 300 mV.
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...