Hi, I have a switch in my kitchen which has a red light on it. This is the power switch for my fridge freezer. I noticed the red light on switch is slightly flickering. Tried to google and all I could find was that the neon bulb might be going. Just wondered if anyone knows what it could be. Many thanks.
Neons go dim and flickery as they age. Ignore it.
Don't worry about it Neon do flicker and possibly more at the end of their life. Even if the neon completely fails and the red light goes out the socket will still work as normal.
A warning light that does not work should always be replaced, covered, or marked as broken, since is necessary to have a warning that the warning light cannot give a warning.
If the OP is willing to spend 21 pence (incl VAT) on a replacement neon then maybe cost effective but otherwise the dead neon will not make any difference to the operation of the switch.
When you open it for a look, it might be an NE-2 family bulb, plus a current limiting resistor. Like this.
Mains ---- 220K limiting resistor -------- NE-2 ------+ | Mains ------------------------------------------------+
(The limiting resistor can be soldered to the defective bulb. You can barely see the solder joint in this picture.)
A bit of polyolefin tubing, can cover the exposed wire legs on the components. Polyolefin tubing comes in three foot lengths, and in various diameters. The diameter chosen, should be double the diameter of the thing to be covered (making allowance for the diameter of the new solder joints or the diameter of the resistor body).
Such tubing is preferred, compared to electrical tape.
*******The specifications can be somewhat misleading.
One bulb is taller than the other, so you can measure the existing bulb, to see which type it is.
Those are two common types. There are some other, very nice larger bulbs, which will be harder to find.
I guess electric fry pans still need those as indicators, and that's why someone still makes them.
If the resistor is too small and you run too much power through them, they "arc over" and there is a secondary lighting reaction. The color is a lot hotter looking (like an angry purple) and if run in that condition for a minute or two, the bulb might crack or melt or burst.
The objective, is to not run the bulb too energetically. That ensures a longer life. And the life is definitely not 25,000 hours trouble free. They will wink and blink and start to fail, well before 25,000 hours has passed. I suppose when the electrodes are well and truly blackened, that will be at the 25,000 hour mark.
The two example bulbs above, have cylindrical electrodes. Some neon bulbs have flat plates, and those can carry a bit more current. Since I don't use those, I can not give a guess as to operating life.
*******This is a separate, irrelevant topic.
Any of the web pages which talk about "relaxation oscillators", the capacitors used for those, are the smaller "orange drop" style ones. I have a tray of caps suitable for that purpose, orange drop ones at 400V and 600VDC. You can build fun little circuits with R and C components and the bulbs will flash repetitively, in a more reliably timed sequence. Not the random flashing they get when the electrodes are worn on them. The capacitor values should be kept low, because if you use too high a value, that puts too many joules through the bulb per flash (they'll go purple on you). Just remember that the supplies used for experiments like that, say 90VDC or ten 9V batteries in series, are dangerous items, because if you're being electrocuted by one, you "can't let go". DC isn't the best choice for muscle contractions. Very nasty.
You can get a tray of resistors for only pennies per resistor, when you buy 100 pak assortments. And this can give some values to play with.
And remember when playing with crap like that, that 0.22uF might stay charged, after the input supply is disconnected. You have to be careful where you stick your fingers and so on :-) I used to play with this stuff as a kid, and I managed to tire of this stuff, without getting stung once. Not all my experiments turned out that lucky. The ignition coil got me pretty good.
I didn't use a plugin breadboard at the time, but breadboards have an upper limit on voltage before they break down. And so there's a limit to how high a voltage you can apply to these. Unfortunately, that's not stated in the datasheet, what the maximum voltage is that can be applied. Some of the orange drop capacitors (the very largest ones I've got), the legs are too stout to fit in the holes. Breadboards like this allow doing experiments, without having to solder stuff, or beat up the legs by twisting the legs on stuff together.
Neon bulbs work with AC or DC. AC lights both legs. DC lights one leg (as polarity dictates).
You will tire of them pretty quickly, and then you'd be stuck with a lifetime supply of "replacement bulbs".
Paul
Well, neons eventually lose their ability to strike, and this tends to end up with flickering. If you can be bothered to take it apart then you could change it, they tend to be little two wire bulbs with a resistor in series with them. How old is it? Brian
However he may rely on the light to tell him if the supply is there.
Brian
It's not a warning light INHO.
It's an indication light.
It might also be a functional light, to ensure the freezer still works at low temperatures.
More reason why a non working light should be replaced with one of the same type.
And the chances of that being true in this case?
And how does the fridge/freezer communicate this status information to a flickering neon in a switch?
"Hi, I have a switch in my kitchen which has a red light on it."
Implies that it is in a 13A wall socket (or possibly a spur box or even a 13A plug) rather than part of the FF. A neon wouldn't generate enough heat to affect the functioning of the FF in any case.
Just get a new wall plate - less than a fiver.
Even cheaper if you buy one without the "optional extra" of a neon indicator:-)
But there is nothing wrong with the existing switch - just the indicator is flickering which it may do for another year before going out.
Might flicker for another 10 years:-)
And that's about the going rate for a reply from homeownershub.
well buy a new neon lamp and fit it
And cheaper still is a piece of white gaffer tape over the light :-)
Or use red for the authentic look.
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