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When was the first electronic bitmap sign invented?
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james_s:

--- Quote from: SL4P on February 08, 2020, 12:30:32 am ---Without reading that article, the consumption of that sign-wall must have been staggering -especially with the inefficient technologies of the time...

Even multiplexed (incandescent?) would have been a huge undertaking, and the RF switching noise would have blocked radio reception for many blocks around!

Non-multiplexed would have used more power than Las Vegas in the 80s !!

--- End quote ---

I don't think it makes any difference if they're multiplexed or not, incandescent lamps respond to RMS power, much like thermal RF power meters, there are no external tricks you can use to make the filament get hotter with less power going into it. Additionally to multiplex incandescent you need a diode in series with each lamp which adds an additional penalty due to the forward drop.

I remember reading years ago that the first programmable electronic sign on the side of some of the Goodyear blimps used 28V incandescent lamps controlled by a minicomputer in the gondola and needed a separate turbine APU slung underneath to power it.
bsdphk:
"Without reading that article, the consumption of that sign-wall must have been staggering"

No, not really.

The bulbs in the old papertape drive mechanisms were seldom even 5W each.
6-
The first one on "Politiken" had 149x9 bulbs so that would probably only be 6-7 kW fully lit.
Brent88:
1920s  had readable bulb based signage

AlbertL:
This film from 1935 looks at the workings of the giant Chevrolet sign in Chicago.  It shows the control equipment for the Motograph and an animated explanation of how it functions.
LaserSteve:
The key to the motograph is using a inert gas filled lamp (Usually Krypton)  for quick cooldown of the filament. Once upon a time I found myself getting a quote for 7,700 of the beasts.

Steve

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