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Default NE-51 Neon Bulbs



"Fred McKenzie" wrote in message
...
In article ,
Madness wrote:

Just acquired a bunch of these lamps. They're in the same mini-bayonet
style as lamps like the #44/47. But would anyone know if these lamps can
be connected directly to 120 volts? Or do they need a resistor, @ if so,
what value?


Madness-

NE-51 does NOT have a resistor inside!

One thing you can do with them, is build a relaxation oscillator. From
a 90 to 100 volt DC source, connect a series resistor, with a capacitor
across the bulb. Perhaps 470K Ohms and 1 uF. Try different values to
change the flashing rate. For smaller values, it can be used as an
audio oscillator.

Another variation is to have several bulbs, each with its series
resistor. But the capacitors are connected from bulb to bulb in a ring.
The result is a somewhat random flashing. I once built one with 5
generic neon lamps using two small 45 Volt batteries in series. Some
people would become engrossed, trying to figure out the flashing
sequence!

Fred


Ha ! I built one too when I was an apprentice. I seem to think that the
circuit was in Practically Witless magazine. There used to be an aerosol
deodorant at the time which had a blue spherical cap. I had about 12 neons
in my version, and had them poked through holes in one of those caps - a bit
like a WW2 sea mine. Quite by chance, the neon that flashed slowest was the
one that poked vertically out of the top. It was all run from a single 90
volt battery, housed in a box made from modeling plasticard under the
deodorant cap. The one thing that I do recall is that it also had a switch
to alter the way the neons flashed. I seem to remember that one leg of all
the neons were joined together and connected to battery -ve. Likewise, one
leg of all the caps were joined together. When they were left 'floating',
the flash of the individual neons was very 'soft' and hypnotic and random.
The switch took the commoned capacitor legs to battery -ve. With the switch
closed, the flashes were much 'sharper' making the whole display much more
'frenetic' looking. The current drain was so small that a battery lasted a
year or more (which was just as well, as they were expensive. I think I
still have a bunch of neons somewhere. I might try knocking one up again ...
:-)

Arfa