NE-51 Neon Bulbs

[Madness]

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?

[Jon Elson]

Oh, you definitely need a series resistor. About 100K is typical.

Jon

[Ian Field]

"Jon Elson" <jme...@wustl.edu> wrote in message
news:3_2dnQ8Xm6h3FNLL...@giganews.com...

Of 3 hits from searching NE51 - voltage rating was stated variously from
105 - 120.

Confusingly, one page displayed a picture of a filament bulb.

If a "bunch" of them is sufficient to sacrifice one, I'd peel the base cap
and see if there's a resistor in there.

Anything with a plastic lens cap probably has a resistor in the base.

Ionisation voltage is usually 70 - 90V, across the mains with a 100k
resistor in series would reveal the volt drop of the bulb - anything much
above 90V suggests an internal resistor.

[M Philbrook]

In article <n2o178$ktt$1...@dont-email.me>, polic...@thedonutshop.com
says...

That lamp is set to operate at 120V AC, so no, you don't need a
resistor. I do think they may be putting one in the base.

A NE-2 however, does need a resistor.

[Ralph Mowery]

"M Philbrook" <jamie_...@charter.net> wrote in message
news:MPG.30b96c56b...@news.eternal-september.org...

While some neon bulbs with a base may not need an external resistor, this
one needs an external resistor.

All the data sheets I looked at states they need an external resistor ,
usually a 220 K .
http://www.bulbtown.com/B1A_NE_51_Neon_Glow_Bulb_BA9S_Base_p/b1a.htm

[hrho...@att.net]

anywhere from 100,000 - 200,000 ohms, 1/2 watt or larger. Smaller resistor, brighter light, shorter bulb life.

[Madness]

Thanks for the replies, everyone. I forgot to mention that my lot (about
30) is of vintage GE NE-51's, not the modern "NE-2 w/ plastic lens" variety.

[Tim Schwartz]

Hello,

While I recall that they need the dropping resistor, since you have a
bunch of them, I might try destructive testing, and break one apart to
see if there is an internal resistor or not.

Regards,
Tim

[Fred McKenzie]

In article <n2o178$ktt$1...@dont-email.me>,

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

[c4urs11]

On Sat, 21 Nov 2015 10:12:31 -0500, Fred McKenzie wrote:

> For smaller values, it can be used as an audio oscillator.

I remember repairing a church organ that used such oscillators,
one for each key... That was some 40 years ago :-)
Sawtooth oscillators do produce a nice sound.

Cheers!

[Michael Black]

Memory says they always needed a resistor, it's not about too much
voltage, but about needed a limited current. The only time they don't
need a resistor is if there is a resistor built in.

Michael

[jf...@my-deja.com]

On Saturday, November 21, 2015 at 5:38:50 AM UTC-8, Tim Schwartz wrote:
> ...I might try destructive testing, and break one apart to

> see if there is an internal resistor or not.
>
> Regards,
> Tim

If you take this approach, it does not have to be destructive. If you own a soldering iron, you can melt the two solder blobs on the bayonet, loosen the cement, and remove the bulb intact. After inspection, you can reglue and resolder, and the lamp will be as good as new.

[Mark Zenier]

In article <n2os3o$59p$1...@dont-email.me>,

Madness <polic...@thedonutshop.com> wrote:
>Thanks for the replies, everyone. I forgot to mention that my lot (about
>30) is of vintage GE NE-51's, not the modern "NE-2 w/ plastic lens" variety.

The 1966 GE Glow Lamp Manual says a B1A (NE-51) draws 0.3 mA
with a 220k ohm resistor at 120 volts.


Mark Zenier mze...@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)

[MJC]

In article <n2ssb...@enews6.newsguy.com>, mze...@eskimo.com says...

> The 1966 GE Glow Lamp Manual says a B1A (NE-51) draws 0.3 mA
> with a 220k ohm resistor at 120 volts.

My recollection of playing with neons in my youth* is that they run
stably at about 50V. Leaving 70V across the 220k resistor. That's pretty
close to 0.3 mA. QED!

* As an apprentice project, I built a clock that used four 5x7 blocks of
neons for a digital display.

Mike.

[MJC]

In article <MPG.30bc10d3d...@news.plus.net>,
gra...@mjcoon.plus.com says...

>
> * As an apprentice project, I built a clock that used four 5x7 blocks of
> neons for a digital display.

See https://picasaweb.google.com/111741851908838288378/CEDRICProject?
authuser=0&feat=directlink

Mike.

[Geoffrey S. Mendelson]

Madness wrote:
> Thanks for the replies, everyone. I forgot to mention that my lot (about
> 30) is of vintage GE NE-51's, not the modern "NE-2 w/ plastic lens" variety.

Note that many neon bulbs had some sort of radioactive doping to get
them to fire at a lower votage.

I don't have any hard data, but I believe it was thorium up until the late
1940's when the US government decided that radioactive material needed
supervision.

It was found to be simpler to just add a small amount of radioactive
krypton gas to the neon. However the half life of the krypton gas is
about 10 years. So neon bulbs made in 1970 would have about 1/20th of
the krypton still radioactive, which is probably no longer able to
make a difference.

Speaking of radioactivity, if you are looking for an unusual project to
make from them, they can be used to make geiger counters.

I don't think they are very sensitive, but if you live in the US, the
red Fesita Ware department of any thrift shop would make it "go nuts".
:-)

Geoff.
--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379

[Ian Field]

"Geoffrey S. Mendelson" <g...@mendelson.com> wrote in message
news:slrnn54ca...@cable.mendelson.com...

> Madness wrote:
>> Thanks for the replies, everyone. I forgot to mention that my lot (about
>> 30) is of vintage GE NE-51's, not the modern "NE-2 w/ plastic lens"
>> variety.
>
> Note that many neon bulbs had some sort of radioactive doping to get
> them to fire at a lower votage.
>
> I don't have any hard data, but I believe it was thorium up until the late
> 1940's when the US government decided that radioactive material needed
> supervision.

Most valves have some radioactive material in the cathode coating to
increase emission, gas mantles also have some as it makes the illumination
more intense.

IWHT: the radioactive content of a neon bulb is insignificant compared to
either of those examples.

[pf...@aol.com]

Mpfffff....

This lamp was used by Zenith and more than a few other manufacturers in the 1950s/1960s as an indicator lamp (on/off) at about the time that radio manufacturers started to become concerned about user-servicing and hot-chassis radios - something that never really bothered them in the past. The worked on the theory that a neon lamp was far less likely to burn out than the old standby #44 or #47, so that loose fingers were less likely to get nipped. ASIDE: Audio devices held on to incandescent lamps (With specific reference to the 47) well into the 80s, before shifting - very slowly - to LEDs or Fluorescent lamps. But, they had transformers on board to isolate the chassis.

It is designed to operate at ~120V AC. It _CAN_ operate at ~120V DC, but only one post will light. It will trip (glow) at about 90V +/-.

Unless there is a voltage dropper in the circuit, it will fail quickly at 220 or 240 V - that is voltages outside of Japan and the Americas. As supplied, it has a 100K resistor in series with the lamp. For conversion to 220V, I have heard values of up to an *additional* 220K in series. Try there and work back if you wish to operate at 220V.

As about 2/3 of my hobby time is dedicated to vintage radios, I am quite familiar with, and keep a bunch of these lamps in my spares-box.

Peter Wieck
Melrose Park, PA

[bud--]

On 11/24/2015 3:32 PM, pf...@aol.com wrote:
> On Friday, November 20, 2015 at 3:55:22 PM UTC-5, 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?
>
> Mpfffff....
>
> This lamp was used by Zenith and more than a few other manufacturers in the 1950s/1960s as an indicator lamp (on/off) at about the time that radio manufacturers started to become concerned about user-servicing and hot-chassis radios - something that never really bothered them in the past. The worked on the theory that a neon lamp was far less likely to burn out than the old standby #44 or #47, so that loose fingers were less likely to get nipped. ASIDE: Audio devices held on to incandescent lamps (With specific reference to the 47) well into the 80s, before shifting - very slowly - to LEDs or Fluorescent lamps. But, they had transformers on board to isolate the chassis.
>
> It is designed to operate at ~120V AC. It _CAN_ operate at ~120V DC, but only one post will light. It will trip (glow) at about 90V +/-.
>
> Unless there is a voltage dropper in the circuit, it will fail quickly at 220 or 240 V - that is voltages outside of Japan and the Americas. As supplied, it has a 100K resistor in series with the lamp. For conversion to 220V, I have heard values of up to an *additional* 220K in series. Try there and work back if you wish to operate at 220V.

It will fail immediately without a series resistor.
As others have said, there is no resistor built into the lamp.

From a 1965 Allied Radio catalog, Chicago Miniature lamp:
NE-51 is clear glass tubular, single contact bayonet base.
Voltage across the lamp is 65V when operating at the rated 1/25 watt.

A higher voltage is necessary to ionize the neon (which is why a
relaxation oscillator works). The voltage is somewhat constant with
varying current. At 1/25 watt and 65 volts the current would be 0.6 mA
and the series resistor for 120V supply would be 91k (minimum).

There is also a NE-51H that runs at a blinding 1/7 watt (2 mA).

[Arfa Daily]

"Fred McKenzie" <fm...@aol.com> wrote in message
news:fmmck-C855FA....@5ad64b5e.bb.sky.com...

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

[jcs74...@gmail.com]

Merči a tous je vais verifier la capacite qui se trouve avant le transfo d alimentation a +merci pour l information

[Cydrome Leader]

Nice case. How old is that thing? What's inside?

[heath...@gmail.com]

Yes antique radios. I like them to with filaments glowing in the tubes.For younger members the tube is old glass bulb valve with the led on top. Some of them have the magic green eye for RF strength if you are lucky enough to find one. Neat trick that you can do with the old variable capacity plate tuner. Charge it to 30 volts with a neon bulb across. When you turn the tuning knob to open the plates the neon bulb will flash? With only 30 volts how could it flash a neon bulb with a 80 volt trigger voltage?

[MJC]

In article <695088d6-14d7-496c...@googlegroups.com>,
heath...@gmail.com says...
> ... Neat trick that you can do with the old variable capacity plate

tuner. Charge it to 30 volts with a neon bulb across. When you turn the
tuning knob to open the plates the neon bulb will flash? With only 30
volts how could it flash a neon bulb with a 80 volt trigger voltage?

I wish I'd thought of doing that. But I'm amazed it works, even with
beautifully cleaned insulators on your capacitor.

Good demonstration of relationship between charge, voltage and capacity.
(Analogue of skater's pirouette?)

Mike.

[Adrian Caspersz]

When I was about 10, I had a Tandy Radio Shack kit of 5 neon bulbs in a
row, that had a plastic box.... oh, hang on - let google find an image ..

(later)

that, the Science Fair Goofy-Lite
http://my.core.com/~sparktron/130P1.JPG

The Radio Shack, Science Fair, P-Box kits
http://my.core.com/~sparktron/pbox.html

Interesting that it flickered differently in the dark, or with ones
finger acted up differently.

Ran from 6V. There was an option of making it sequential rather than random.

Schematic
http://my.core.com/~sparktron/130P6.JPG


I also built the Three Transistor Short Wave Regenerative Receiver kit
http://my.core.com/~sparktron/110P1.JPG

Happy Days. Had to be quick with the soldering iron or the box would melt :)

--
Adrian C

[John Heath]

Thanks for the trip down memory lane. 50 cents for the whole kit , that had to be the 1950s or 1960s. And the 1 tube AM radio with a 1T4 tube from your second link. That was way cool.

[John Heath]

Great analogy. The more I think of it the hands and feet coming in for a faster pirouette is exactly the same.

[Ian Field]

"Adrian Caspersz" <em...@here.invalid> wrote in message
news:ddvk1j...@mid.individual.net...

My first transistor SW regen was at boarding school - the cop shop relay
antenna was in a compound a few hundred yards from the school grounds, they
used SW back then too.............

[MJC]

In article <n3qge0$hc3$3...@reader1.panix.com>, pres...@MUNGEpanix.com
says...

Kind of you to take an interest! The whole project was carried out in
1964 (when I became 21). The neons were directly driven via a diode
array which encoded from up to ten numeral lines per digit. But I don't
remember whether we fitted all those diodes (I still have circuit
diagrams squirreled away!) into the display box or whether the cable has
5x7x4 wires, one per neon. There was a much bigger box which held the
rest of the circuitry and the large battery...

Mike.