Neon light for AC outlet tester.

[David Farber]

I have one of those polarity/line/ground checker plugs. It has three lamps
that illuminate according to the condition of the 120VAC outlet. The neon
light that illuminates indicating a good ground is not lighting up anymore.
Will this replacement neon light work properly for this application?

https://www.digikey.com/product-detail/en/visual-communications-company-vcc/C2A/C2A-ND/3150384
There is a 68k resistor in series with the lamp. What does the breakdown
voltage indicate?
http://www.vcclite.com/_pdf/Neon%20Indicator%20Lamps_7_&_8.pdf

A picture of a similar tester is here.
http://www.acehardware.com/product/index.jsp?productId=3099752

Thanks for your reply.
--
David Farber
Los Osos, CA

[pf...@aol.com]

On Monday, November 6, 2017 at 1:36:54 AM UTC-5, David Farber wrote:

>
> A picture of a similar tester is here.
> http://www.acehardware.com/product/index.jsp?productId=3099752

99-44/100ths of neon applications of this nature use the NE-2 or NE-2E lamp. Both will need a 'ballast resistor' of about 100K ohms. Which is also the part that may have failed in your tester.

Peter Wieck
Melrose Park, PA

[tschw...@gmail.com]

Before I cracked the case on a "safety" tool, I'd probably decide to just buy another.... I've seen these for about $5 at Harbor Freight and similar stores.

[tabb...@gmail.com]

Yes, as long as there is a suitable resistor in series with it.


NT

[Jeff Liebermann]

The common NE-2 neon lamp will work just fine. I've never bothered to
tear one apart so I don't know what's inside. Looks like there are
different design schemes:
<http://www.giangrandi.ch/electronics/neon/simple.html>
<http://www.electro-tech-online.com/threads/information-about-electric-tester-circuit.132363/#post-1104807>
<http://www.marcspages.co.uk/pq/4511.htm>
<http://www.electro-tech-online.com/attachments/sch-1a-png.87460/>

I doubt that the NE-2 lamp is the problem. My guess(tm) is something
fell apart or came loose inside. Probably a bad crimp.


--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[J.B. Wood]

On 11/06/2017 01:36 AM, David Farber wrote:
> I have one of those polarity/line/ground checker plugs. It has three lamps
> that illuminate according to the condition of the 120VAC outlet. The neon
> light that illuminates indicating a good ground is not lighting up anymore.
> Will this replacement neon light work properly for this application?

Hello, and these testers (with or without GFCI test capability) are very
simple devices consisting of three neon lamps with ballast resistors
connected line-neutral, line-ground and neutral-ground. Your main
problem I think is that these testers usually are encased in a molded
liquid-resistant rubber-like enclosure. Buying a replacement unit might
be more feasible. Also, depending on the tester manufacturer, the
pattern of of the 3 lamps (on or off) for the same outlet condition can
be different. Sincerely,


--
J. B. Wood e-mail: arl_1...@hotmail.com

[David Farber]

Jeff Liebermann wrote:
> On Sun, 5 Nov 2017 22:36:43 -0800, "David Farber"
> <farberbe...@aol.com> wrote:
>
>> I have one of those polarity/line/ground checker plugs. It has three
>> lamps that illuminate according to the condition of the 120VAC
>> outlet. The neon light that illuminates indicating a good ground is
>> not lighting up anymore. Will this replacement neon light work
>> properly for this application?
>>
>> https://www.digikey.com/product-detail/en/visual-communications-company-vcc/C2A/C2A-ND/3150384
>> There is a 68k resistor in series with the lamp. What does the
>> breakdown voltage indicate?
>> http://www.vcclite.com/_pdf/Neon%20Indicator%20Lamps_7_&_8.pdf
>>
>> A picture of a similar tester is here.
>> http://www.acehardware.com/product/index.jsp?productId=3099752
>
> The common NE-2 neon lamp will work just fine. I've never bothered to
> tear one apart so I don't know what's inside. Looks like there are
> different design schemes:
> <http://www.giangrandi.ch/electronics/neon/simple.html>
> <http://www.electro-tech-online.com/threads/information-about-electric-tester-circuit.132363/#post-1104807>
> <http://www.marcspages.co.uk/pq/4511.htm>
> <http://www.electro-tech-online.com/attachments/sch-1a-png.87460/>
>
> I doubt that the NE-2 lamp is the problem. My guess(tm) is something
> fell apart or came loose inside. Probably a bad crimp.

Hi Jeff,

I opened it up and the crimps and resistors are good. Do you have any idea
what the lamp's breakdown voltage specification indicates? According to the
datasheet, the NE-2 has a breakdown voltage of 65VAC. The high brightness
bulbs have a higher breakdown voltage of 95VAC.

[Pat]

On Mon, 6 Nov 2017 10:01:55 -0800, "David Farber"

You do know that only 2 of the three bulbs should be lit for a good
outlet, right? The ones going from hot to ground and hot to neutral
should be on. The one going from neutral to ground is always off
unless hot and neutral have been swapped due to a wiring mistake.

[pf...@aol.com]

On Monday, November 6, 2017 at 1:50:33 PM UTC-5, Pat wrote:

> You do know that only 2 of the three bulbs should be lit for a good
> outlet, right? The ones going from hot to ground and hot to neutral
> should be on. The one going from neutral to ground is always off
> unless hot and neutral have been swapped due to a wiring mistake.

Yes. Like this:

http://www.liberty-hi-railers.com/images/outlet_tester.jpg

The neutral line lights only when there are swaps, and only in two of five conditions.

[David Farber]

Hi Pat,

I am aware that only two of the three bulbs are supposed to light under
normal circumstances. The hot to ground light is not working which is giving
the false indication that the ground is open when in fact the ground is in
good condition.

[whit3rd]

On Sunday, November 5, 2017 at 10:36:54 PM UTC-8, David Farber wrote:
> I have one of those polarity/line/ground checker plugs. It has three lamps
> that illuminate according to the condition of the 120VAC outlet. The neon
> light that illuminates indicating a good ground is not lighting up anymore.

Yes, that replacement will work fine. So will almost any neon lamp that
physically fits. Your cost, after shipping, will be a little more than the
cost of a new checker plug...

These lamps can fail because of slow gas leakage, so if the other two
seem dim, or flicker, it might be prudent to swap them out as well.

[David Farber]

Someone in this group mentioned a while back that if you send a check or
cash and prepay your order to Digi-Key, you get free shipping no matter how
small your order. That helps out when you only need a few parts.

[tabb...@gmail.com]

On Monday, 6 November 2017 18:50:33 UTC, Pat wrote:
> On Mon, 6 Nov 2017 10:01:55 -0800, "David Farber"
> <farberbe...@aol.com> wrote:
> >Jeff Liebermann wrote:
> >> On Sun, 5 Nov 2017 22:36:43 -0800, "David Farber"
> >> <farberbe...@aol.com> wrote:
> >>
> >>> I have one of those polarity/line/ground checker plugs. It has three
> >>> lamps that illuminate according to the condition of the 120VAC
> >>> outlet. The neon light that illuminates indicating a good ground is
> >>> not lighting up anymore. Will this replacement neon light work
> >>> properly for this application?
> >>>
> >>> https://www.digikey.com/product-detail/en/visual-communications-company-vcc/C2A/C2A-ND/3150384

> You do know that only 2 of the three bulbs should be lit for a good
> outlet, right? The ones going from hot to ground and hot to neutral
> should be on. The one going from neutral to ground is always off
> unless hot and neutral have been swapped due to a wiring mistake.

Modern units seem to use more complex circuits where all 3 normally light.


NT

[pf...@aol.com]

On Monday, November 6, 2017 at 4:02:35 PM UTC-5, tabb...@gmail.com wrote:

> Modern units seem to use more complex circuits where all 3 normally light.

Which he does not have.

I also have an analyzer

https://i.ytimg.com/vi/Bbwh4n9hplk/maxresdefault.jpg

He does not have that, either.

[Jeff Liebermann]

On Mon, 6 Nov 2017 10:01:55 -0800, "David Farber"
<farberbe...@aol.com> wrote:

>I opened it up and the crimps and resistors are good.

Well, so much for the easy fix.

When you inscribed:

"The neon light that illuminates indicating a good ground
is not lighting up anymore".

Which of the 3 lamps are you referring to?
<https://images-na.ssl-images-amazon.com/images/I/81IbbdT22JL._SL1500_.jpg>

I would guess(tm) that this is what you found inside:
<https://www.nachi.org/forum/attachments/f19/11495d1178925009-outlet-reading-three-prong-tester-schematic.jpg>

>Do you have any idea
>what the lamp's breakdown voltage specification indicates? According to the
>datasheet, the NE-2 has a breakdown voltage of 65VAC. The high brightness
>bulbs have a higher breakdown voltage of 95VAC.

It's not a high brightness NE-2H or NE-2UH lamp.

Neon lamps have a V/I curve with hysteresis. They turn on at about
65VAC, and stay turned on until the voltage drops below about 50VAC
(maintaining voltage). The actual voltages are not very well
controlled and are affected by ambient lighting, radiation, and
temperature. In between these two points, the neon lamp exhibits
negative resistance, which makes a dandy relaxation oscillator or
logic circuit.

Drivel: I'm reading from the "GE Glow Lamp Manual" 2nd edition 1966.
GE never made an NE-2. The closest equivalent is their 3AG lamp).
<http://www.introni.it/pdf/GE%20Glow%20Lamp%20Manual.pdf> (12.1MB)

[tabb...@gmail.com]

On Tuesday, 7 November 2017 07:09:20 UTC, Jeff Liebermann wrote:
> On Mon, 6 Nov 2017 10:01:55 -0800, "David Farber"
> <farberbe...@aol.com> wrote:
>
> >I opened it up and the crimps and resistors are good.
>
> Well, so much for the easy fix.
>
> When you inscribed:
> "The neon light that illuminates indicating a good ground
> is not lighting up anymore".
> Which of the 3 lamps are you referring to?

it would have to be the L-E one.


NT

[David Farber]

Hi Jeff,

https://www.nachi.org/forum/attachments/f19/11495d1178925009-outlet-reading-three-prong-tester-schematic.jpg
This is the correct diagram except the resistors are not 47k, they are 68k.

On page 81 of the GE Glow Lamp Manual, there is an interesting test circuit.
It shows the neon light in a box with another light source. I think it
explains why my ~20 year old battery powered fluorescent book lamp doesn't
work very well at night when I use two rechargeable AA batteries. The lower
voltage isn't able to turn on the lamp when there is no ambient light. I
have to shine a flashlight on the lamp to get it to come on. When the
batteries get a bit drained, it can take almost a minute for the light to
come on with the flashlight trick. Once it's on, it provides very nice, even
lighting.

[Jeff Liebermann]

On Wed, 8 Nov 2017 09:04:42 -0800, "David Farber"
<farberbe...@aol.com> wrote:

>https://www.nachi.org/forum/attachments/f19/11495d1178925009-outlet-reading-three-prong-tester-schematic.jpg
>This is the correct diagram except the resistors are not 47k, they are 68k.

The exact value isn't important. There's some effect on the
brightness, but not much.

>On page 81 of the GE Glow Lamp Manual, there is an interesting test circuit.
>It shows the neon light in a box with another light source. I think it
>explains why my ~20 year old battery powered fluorescent book lamp doesn't
>work very well at night when I use two rechargeable AA batteries. The lower
>voltage isn't able to turn on the lamp when there is no ambient light. I
>have to shine a flashlight on the lamp to get it to come on. When the
>batteries get a bit drained, it can take almost a minute for the light to
>come on with the flashlight trick. Once it's on, it provides very nice, even
>lighting.

Yeah, that makes sense. The test setup shows that the light source is
0 to 500 ft-candles which converts to about 5400 lux. That's rather
bright, especially when measured 1 ft away. (I just tried it with my
LED flashlight and lux meter).

A variation on the same test is to add something radioactive inside
the neon lamp. The idea is for the neon to ionize at a lower voltage,
thus making a better voltage regulator, memory device, or whatever.
Radioactivity is also used to help fluorescent tubes start:
<http://www.irpa.net/irpa10/cdrom/00740.pdf>
Half-Life Emits
Kypton-85 10.8 years Beta
Promethium-147 2.6 Beta
Tritium H3 12.3 Beta
Thorium-232 14 billion years Alpha

My guess(tm) is that your 20 year old fluorescent tube had some kind
of starting help from some radioactive material, which is long gone by
now.

[bruce2...@gmail.com]

On Mon, Nov. 6, 2017 at 1:50PM, Pat wrote:
>
> You do know that only 2 of the three bulbs should be lit for a good
> outlet, right? The ones going from hot to ground and hot to neutral
> should be on. The one going from neutral to ground is always off
> unless hot and neutral have been swapped due to a wiring mistake.

I like those wire strippers with the built-in hot stick in the handle area.

[Ralph Mowery]

In article <otq861$ns6$1...@dont-email.me>, farberbe...@aol.com
says...

>
>
>
> I opened it up and the crimps and resistors are good. Do you have any idea
> what the lamp's breakdown voltage specification indicates? According to the
> datasheet, the NE-2 has a breakdown voltage of 65VAC. The high brightness
> bulbs have a higher breakdown voltage of 95VAC.
>
>

The voltage will not make much difference.

Many of the common neon bulbs will take about 90 volts to light. When
they do light they act almost like a voltage regulator and will have
about 70 volts across them no matter what the current is (within limits
of blowing up) The higher brightness bulbs will often have more voltage
across them. The resistor is to limit the current though them to a safe
level. On an AC circuit you will have over 150 volts peak so most any
common bulb will fire off.

If you have a way of slowly raising the voltage on the bulbs, you can
check at what voltage they first light at. Then cut the voltage off and
drop it to about 10 volts below that voltage. Then just touch the bulb
and it will fire off. The extra heat eill be enough to make it light
up.

[David Farber]

Hi Ralph,

Thanks for the great explanation.