On 2016-May-24, at 11:58 AM, Swift Griggs wrote: > On Tue, 24 May 2016, Marc Howard wrote: >> Those aren't LED's on the Apollo display. They are EL's (Electro >> Luminescent displays). Each segment of each digit was controlled by a >> relay. They astronauts eventually got use to the tinkling sound of the >> relays. > > Is that the same as the EL that was used in the 1980's on lots of old > stereo gear ? Ie.. you'd hit rewind and some little backlit > glass-and-silkscreen template would say "Rewind" in blue or green or etc.. > > I LOVE the way that looks. That's one of the reasons why I love the Amiga > CD32 (not that I own one.... yet). It looks like a hifi stereo component > from the 1980s. I have a Kenwood electronic EQ and spectrum analyzer that > has all kinds of EL elements on the front of it. I still use it daily. > It's awesome.
You might be thinking of vacuum-flourescent displays, the green or green-blue displays prevalent on calculators, VCRs, microwave ovens, etc. in the 70-90's (sometimes with some red phosphor). The principle of VF displays is essentially that of a CRT: vacuum bottle with hot filament emitting electrons accelerated to an anode to hit a phosphor to emit light. EL (Electro-luminescent) is another technology that more-directly excites the phosphor with an AC supply. No vacuum bottle or hot filament. Nowhere near as prevalent as VF.
