Front panel switches - what did they do?
Brent Hilpert
hilpert at cs.ubc.ca
Tue May 24 14:18:32 CDT 2016
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.
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