On 2016-Aug-21, at 6:06 PM, Mouse wrote: > A Beckman/Berkeley model 5230 "UNIVERSAL EPUT® AND TIMER", whatever > that is. The most visually notable feature is that it has four display > columns with ten digit positions in each one, presumably with a lamp > behind each position.
These are digital electronic counters implemented with vacuum tubes. EPUT = Event Per Unit Time, i.e. frequency. Ten neon lamps for each digit of the readout. If you want a manageable (and obtainable) example of tube-based digital electronic technology this would be a choice.
