In message <20010228.132730.-237529.0.haroldhallikainen@juno.com>, Harold M Hallikainen writes > Speaking of old technology, anyone remember the (RCA, I think) Numitron >display? It was a seven segment display using incandescent filaments. You >could use them just like an LED seven segment, but could not multiplex >them without adding a bunch of diodes. I can't say I remember the trade name, but when I was at Technical College in 1973 I was involved in building a project using seven segment filament displays. It was based on a simple block diagram, using three displays with just the horizontal filaments used, and was a simple 'slot machine'. It consisted of ring of three counters feeding each display, fed from astable oscillators via bistable latches. The three displays cycled round, and you had to press three buttons to light up a single line to win, win or lose was indicated by bulbs fed from a combination of AND and OR gates. This was built using only discrete components, and had to be built on plain matrix board with all wiring and components on the top of the board. The completed machine (with a transparent perspex top was exhibited at the college open day!. -- Nigel. /--------------------------------------------------------------\ | Nigel Goodwin | Internet : nigelg@lpilsley.co.uk | | Lower Pilsley | Web Page : http://www.lpilsley.co.uk | | Chesterfield | Official site for Shin Ki and New Spirit | | England | Ju Jitsu | \--------------------------------------------------------------/ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.