Amateur Question on an Archaic Topic,

[Sean the Nailer]

Hello, and Greetings.
Please excuse my naivete, but my google-fu is dreadful and I'm beyond frustrated in searching for a calculator for finding the necessary resistor to complete a circuit of 6 or 8 Neon bulbs.
I have the bulbs, which came with little information, from an ebay supplier. They DID come with a resistor pre-soldered on each bulb. As I am understanding, when I want to use more than one in a circuit I then need to remove all of the attached resistors and install ONE resistor instead. The question is, I don't know how to find out what the resistor value should be.

And I've been trying to word the question in search-engines every which way from Sunday, and am getting practically no luck. I am not a professional electronicologist. Though I have played with various electronic component and circuits through my lifetime already, this is my first foray into Neon tubes. Little tiny 'indicator' type tubes.
40 Pcs 5x10mm Head Orange Light Neon Bulb Indicator Lamp 100V-220V w Resistor
The above is the title/description directly from the auction. In this case, the resistors are "Brown-Green-Yellow-Gold". Also, this is for 120v AC circuit.

If I knew that there were other questions that I should have asked here, I would ask them. If there's something else that I'm missing, please feel free to advise me, and/or point me in the correct direction.

Then end application of these bulbs, is simply accent lighting for a set of living-room lamps that I've build for my Lady. It's a fairly lengthy story, but I can easily supply pictures here of the end result if anyone wants to see it/them in the end.

Your assistance and patience is appreciated, and I look forward to any/all replies and comments.

Thank you.

 

[Tony Stewart]

You cannot share one resistor for all tubes as each may have a different avalanche threshold and then once reached the 1st clamps down in voltage preventing the others from ionizing.

Just run each with independent R's across the line.

 

[Sean the Nailer]

Wow, thank you Tony for the quick response. I guess I've been misinformed, and I appreciate your help. Can you tell me then, which would be best for these, circuit wise? Series, or parallel? I'm assuming parallel, myself. But I've been known to be wrong before.

 

[Tony Stewart]

YOu would expect them to work in different rooms. Now is that series or parallel?

 

[JimB]

Your neon lamps should be connected in parallel across the 120v mains supply.
Each lamp must have its own resistor.
The colour banding on the resistors means that they are 150,000 Ohm, often just abbreviated to "150k", the gold band means that the value has a tolerance of +/-5%.

The lamps would not work in series.
Those small lamps need about 75 volts before they will strike, ie light up.
When they are lit up, the voltage across them is usually about 60 volts.
This is why you need the resistor, to "soak up" the difference in voltage between the supply and the lamp.
Soak-up is not a very technical term, but I think it describes what is going on quite well.

JimB

 

[dr pepper]

Even if you had enough volts to light them all in series things wouldnt work too well, not all the neons will have the same properties.
If you really had to light them all in series then a current limited eht generator might be better, but forget that for something that needs to be remotely reliable.

 

[alec_t]

The resistor that is already in series with the neon will have been selected to limit the neon current to a suitable safe level. Don't be tempted to change it.

 

[Tony Stewart]

If a value of 150k is used for both 120Vac and 240Vac, the voltage across the tube will be constant and thus R controls the current which affects the glow brightness. Doubling the current in the B range ( such as operating from 240V) will reduce the lifetime to 10% of the expected 30kh or 3kh.

In theory you can operate 2 tubes in series with one smaller R, but the brightness and life expectancy would vary greatly with line voltage which must be a lower tolerance like 115~120Vac

 

[Tony Stewart]

Here the slope is 150k