24 May
2016
24 May
'16
12:18 p.m.
On 2016-May-24, at 11:58 AM, Swift Griggs wrote:
On Tue, 24 May 2016, Marc Howard wrote:
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.
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.