This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time. The circuit is from the 90's, not being given the power supply.
a This very low voltage regulator supports input voltages from 1.7 V to 5.5 V and is suitable for IoT...
The purpose of this 1965 Radio Electronics circuit is to help observe cycloid waveforms on an...
This powerful source was obtained in an American documentation of the 80s. Some components are...