Strange Neon. Stays on after being unplugged. Why?

Reloadron

Joined Jan 15, 2015
7,501
It took about 30 seconds to fully extinguish (or to dim so low I couldn't see it).
My guess is only a single element can be glowing but during normal operation then both would appear to glow. A normal NE2 which is likely among the most popular will ionize at right about 65 VAC (90 VDC) and will remain ionized Once ionized, a lower voltage will maintain the operation of the lamp. The maintaining voltage is usually 10-20 volts below the starting voltage, depending on the lamp and the operating current. For lamps operating on AC voltages of 60 Hz or higher frequency, the light output will appear to the eye as continuous. I may be off a little on those numbers but they are close.

Since the AC changes direction 60 times a second I can't see how once the AC is removed the lamp could continue to glow, not with AC anyway. That only leaves us DC wondering where it is coming from? The theory of anything acting as a capacitor is hard to take since everything about this is AC.

Years ago I have seen neon lamps like the NE2 used to indicate the presence of high voltage DC in power supply designs. When power was removed (AC Mains) they would continue to glow until any HV DC was bled down normally across a bleeder resistor. However, none of that would apply with the vaporizer circuit. I would love to look across that neon lamp with a scope when power is removed or since we are looking at 30 seconds even a DMM. Something is just strange about this.

Ron
 

Reloadron

Joined Jan 15, 2015
7,501
The vaporizer circuit itself is strange to me. Doesn't it cause a bunch of electrolysis?
The advantage in the example provided uses AC which will reduce any chemical buildup on the electrodes as a result of electrolysis. My guess would be following use the user is expected to clean and wipe down the electrodes. Reminds me of the old steam vaporizers I grew up with. When congested with a bad cold or flu like symptoms our mother would get one of our father's old T shirts. Smear Vicks Vap-O-Rub all over our chest, cover that with a half dozen Kleenex and then put the old T shirt on you. The steam vaporizer had a cup below the steam nozzle which was filled with the same Vicks-Vap-O-Rub and you were tucked in for the night. When the water dropped below the electrodes the steam stopped and game over. :)

Anyway using AC has its advantages over DC as to corrosion building up.

Ron
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
7,853
The vaporizer circuit itself is strange to me. Doesn't it cause a bunch of electrolysis?
I've messed with HHO systems - only to learn the hard way that it's a wasted endeavor as you can't get more energy out than you put in. That said, with AC there is some electrolysis. The design is intended to send current through the water, thus heating it to a boiling point. Here at 4550 feet elevation water boils around 208 to 209 degrees F. The boiler begins venting steam within a few minutes of being on. When power is removed the steam stops immediately. Not like the older style heater type warm steam generators. Those older types had to come up to temperature. When power was shut off - there was still some, what I like to call (though incorrectly) "Thermal Inertia". Meaning even though the power has stopped flowing, the element is still red hot (but not so in water).

The way the above pictured steam generator works is by passing current through the water. If it doesn't begin steaming within 10 minutes the manufacturer recommends adding a pinch of salt. A PINCH! Doesn't take much. And the more you put in the higher the current, and the higher the temperature on the wiring and electrodes. Since I run a water softener, there's enough salt in the line to ensure conduction. Hydrogen and oxygen gasses that are generated are not confined and allowed to escape into the atmosphere. Hydrogen being the lighter, it dissipates more quickly. But even the amount of oxygen isn't very high. And it's dispersed into atmosphere too.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
7,853
The advantage in the example provided uses AC which will reduce any chemical buildup on the electrodes as a result of electrolysis. My guess would be following use the user is expected to clean and wipe down the electrodes. Reminds me of the old steam vaporizers I grew up with. When congested with a bad cold or flu like symptoms our mother would get one of our father's old T shirts. Smear Vicks Vap-O-Rub all over our chest, cover that with a half dozen Kleenex and then put the old T shirt on you. The steam vaporizer had a cup below the steam nozzle which was filled with the same Vicks-Vap-O-Rub and you were tucked in for the night. When the water dropped below the electrodes the steam stopped and game over.
Yeah, I remember those old vaporizers and Vick's Vap-O-Rub. Today they have an oil you can put into the water. As for cleaning off the electrodes, there doesn't seem to be the intention of the user accessing that part as the two screws that hold the head unit together are Torq's screws - AND they are inside a chamber that can not be accessed without pulling the unit apart. Perhaps that's the intent - that these, what seem to be, carbon rods wear and become ineffective and thus you have to buy a new unit. I've used this unit for about a year. A few weeks ago when I took it apart these rods appeared to have dissolved somewhat down near the bottom of the rods. And every evening when I refill it I have to drain the remaining water first, which is often slightly colored black. Likely from these rods dissolving.

As to whether they're producing hydrogen and oxygen, I don't know. Actually I don't even care. Here in Utah, in the winter time air is dry. Run a gas fired furnace with forced hot air and the air is even dryer. So running the humidifier helps a lot. My wife doesn't have to use the ear plugs nearly as much as when we don't run it (due to my snoring).
 

Reloadron

Joined Jan 15, 2015
7,501
As for cleaning off the electrodes, there doesn't seem to be the intention of the user accessing that part as the two screws that hold the head unit together are Torq's screws - AND they are inside a chamber that can not be accessed without pulling the unit apart. Perhaps that's the intent - that these, what seem to be carbon rods wear and become ineffective and thus you have to buy a new unit. I've used this unit for about a year. A few weeks ago when I took it apart these rods appeared to have dissolved somewhat down near the bottom of the rods. And every evening when I refill it I have to drain the remaining water first, which is often slightly colored black. Likely from these rods dissolving.
Thanks Tony as I was curious about that and wrongly assumed cleaning the electrodes was a user function. Now back to why does the lamp glow after power is removed? :) This is really strange.

Ron
 

SLK001

Joined Nov 29, 2011
1,549
I had one of these vaporizers and let me tell you that it DID build up a HUGE amount of calcium on the electrodes. I had to routinely scrape the deposits off the elements, which were a pain to get to. I guess that build up is dependent on where you live and your water source. My supply was chocked full of minerals, which readily clogged the two elements. If no maintenance was performed, the steam output would slowly diminish to zero, as the elements got more and more isolated from the water.
 

MisterBill2

Joined Jan 23, 2018
18,176
Heat will also make the neon gas glow, and if the lamp is warm enough, and on top of such a resistance heating system certainly it is warm, it can continue to glow until the temperature inside the bulb drops a bit. Elementary physics, really. OR, you may be located near an intense RF field. That can make a neon bulb glow with the two leads soldered together.
 

Delta Prime

Joined Nov 15, 2019
1,311
In the below image is a NE2 lamp.
View attachment 193828

Working from left to right the first image has DC applied and the element on the right inside the bulb is the negative. The center image also has DC applied and the element on the left is negative. The last image on the right has AC applied so note that both elements are glowing or actually only appear that way in the image because the elements are changing which one glows 60 times a second with 60 Hz power or 50 times a second with 50 Hz power. When a neon lamp reaches its "strike" voltage the gas in the envelop is ionized and the lamp is pretty much a short circuit, thus the need for the series resistor. Matter of fact before high voltage zener diodes neon lamps were used as voltage regulators, well neon and other gases.

So here is the question. Once AC power is removed, the vaporizer unplugged, how does the lamp look? One element remains glowing which would infer a DC presence or both elements glowing which would be a presence of AC and if the lamp continues to glow with both elements where is AC coming from?

Ron
Elementary physics, really. OR, you may be located near an intense RF field. That can make a neon bulb glow with the two leads soldered together.

I love a mystery I wonder what the neighbors are doing?
 
A reminder about Neon lamps. The concept is used in plasma displays. Some nominal DC value is applied across the lamp. That voltage is either "raised a bit briefly" to turn it on and "lowered a bit briefly to turn it off".

Not sure if this plays a part.
 

Analog Ground

Joined Apr 24, 2019
460
I pretty much slept through physics and chemistry but, IMHO, thinking of the after glow as a circuit or rf receiver needing a power source is incorrect. My money is on the glow coming from a florescent material or a neon plasma. Think aurora borealis. Temperature, ions, etc.
 

pmd34

Joined Feb 22, 2014
527
Is there not just a capacitor in the device that powers the neon bulb for a while after power has been disconnected? They use VERY little power.
 

AlbertHall

Joined Jun 4, 2014
12,345
Is there not just a capacitor in the device that powers the neon bulb for a while after power has been disconnected? They use VERY little power.
I am beginning to suspect that the cable could form that capacitor. If that is the case then how long the glow lasts, and which electrode of the neon it is on, should depend on the part of the supply cycle when it is disconnected. Over to you @Tonyr1084
 

SLK001

Joined Nov 29, 2011
1,549
In this case the electrodes are carbon and you can't "anodize" carbon.
I doubt it. Probably as cheap as can be made, so they are steel (mine were steel). And this ain't no battery. To make a battery, you need two dissimilar metals in addition to the electrolyte and I assure you that both electrodes are identical.
 

MisterBill2

Joined Jan 23, 2018
18,176
I pretty much slept through physics and chemistry but, IMHO, thinking of the after glow as a circuit or rf receiver needing a power source is incorrect. My money is on the glow coming from a florescent material or a neon plasma. Think aurora borealis. Temperature, ions, etc.
I paid attention in both of those classes and learned a lot that has been useful over the years.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
7,853
Heat will also make the neon gas glow, and if the lamp is warm enough, and on top of such a resistance heating system certainly it is warm, it can continue to glow until the temperature inside the bulb drops a bit. Elementary physics, really. OR, you may be located near an intense RF field. That can make a neon bulb glow with the two leads soldered together.
After reading your comment I think you hit on the answer. Yes, the top of the vaporizer DOES get warm and stay warm for a few minutes after shut down.
I am beginning to suspect that the cable could form that capacitor. If that is the case then how long the glow lasts, and which electrode of the neon it is on, should depend on the part of the supply cycle when it is disconnected. Over to you @Tonyr1084
Last night I tried plugging it in for an hour then pulling the plug. The lamp glowed slightly, as has typically been the case. Certainly enough glow to notice it - even behind the green plastic lens. Nevertheless, on the subject of the power cord acting like a capacitor - I tried shorting the leads using a nail and that did not cause the bulb to extinguish.

As far as the rods are concerned, I believe I said I THINK they're carbon. They certainly look like they are. As for minerals in the water collecting, I have soft water all throughout the house; so I've not seen any deposits building up the one time I had it opened for cleaning.

@pmd34 no, no capacitors at all.
@MisterBill2, no, no RF transmitters. Not unless ET has secretly taken up residence near by.
@KeepItSimpleStupid Nope. the simplest circuit there could be. To maintain a slight voltage and fluctuate above and below ignition/sustain voltages would require (I think) a DC voltage and a bit more sophisticated circuitry.
 
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