Did anyone notice on the graph how there's a trickle of current that flows before the bulb strikes when there's light present? The line is flat before it strikes without light.
I wonder what would happen if you ran the experiment in the opposite direction, a voltage sweep from 100V to 80V. My guess is that with increasing voltage there is some breakover point at which the bulb overcomes a sort of "electrostatic inertia" and once current is flowing the bulb reinforces the current. It would be interesting to see if the shut off voltage is the same as the start up voltage.
Ive noticed if you have a florescent lamp that flickers as it starts you can make it start much better by shining a light on it as you try and start it. I have 15w flourescent laps ion each side of my medicine cabinet and in the winter when that room tends to be very cool the tubes have a hard time strting in a cooll room so I usually flip on the overhead light before trying to start those lamps beside the medicine cabinet. Ive also noticed that the starters on those lamps work well when new but soon lose their "punch" and if you take the starter can apart you find the little NE2 type bulb inside the starter has become silvered on the inside. A couple of years ago i noticed the lamps were getting harder to start so i ordered some starters on ebay and those seemed to start the flourescebt tubes much faster. Out of curiosity I peeled one of these open and found the neon lamp they used was significantly larger (over 1/2" in diameter) than a NE2 (1/4") and looking in the catalogs I can't find anything that looks like the bulbs the Chinese used inside these starters. I suspect these larger neon lamps are just more robust and are not getting slammed by the discharge current.
I just did the same experiment on my flickering neon lamp with a small UV flash light. Yes, it did make it stop flickering. Thanks for very interesting video!
Early models of the HP 110T Spectrum Analyser used a Neon bulb as a 'zener' for 80V. I think in the service manual it lists the use of a special Neon bulb with extra striking power due to radiation. I was always told it was thoriated coating on one of the electrodes but the gas makes more sense.
Spark gaps used to incorporate little dots of radioactive "paint" inside their envelopes to stabilize breakover voltage. I think this is less common now.
The breakdown voltage under a light stimulus depends on the amount of decay of the radioactive material (e.g Kr-85) and hence the age of the bulb. RF energy can extert a similar effect on neon bulbs.
Fun video, thanks. YOU may be affecting the main experiment, because of the interval between tests : ) Perhaps you could make your script launch 100 tests, alternating, with and without the light. The results could be averaged out. Going further, a photodiode or phototransitor could be used to graph when the lamp lights. Perhaps some older and cheaper-new neon bulbs may not have the special sauce for easy starting. At the computer museum, a docent said that one of the vacuum tube computers, such as the ENIAC or something like that--would give different results if the lights were on or not, which would have been quite upsetting.
Interesting idea. You could probably get rid of that by placing the bulb on a warming element that would raise it's temperature enough that it would be shedding heat even in the presence of a light. You could also run the experiment without any change of light and see if the heat does create enough free electrons to make a difference. Obviously heat can create free electrons, since that's basically how vacuum tubes work.
Is it possible to access your code for this? I’m doing a similar experiment at the moment and i love the feature where you set limits on the voltages you’re reading to narrow down the turn on point!
Radioactive element probably added because manufacturers didn't understand work function or it was cheaper solution. Now, a small % of Ar or H added to help kick off Ne ionization. However, key issue is work function of electrode. Nickel probably used as electrode material with coating of Ba or Sr because they have low work function. Neon bulb becomes flickerish when this coating sublimates. Alkali metals have lower work function, but they have low melting points. Cool science that visible light can be used to demonstrate photoelectric effect.
Did anyone notice on the graph how there's a trickle of current that flows before the bulb strikes when there's light present? The line is flat before it strikes without light.
I wonder what would happen if you ran the experiment in the opposite direction, a voltage sweep from 100V to 80V. My guess is that with increasing voltage there is some breakover point at which the bulb overcomes a sort of "electrostatic inertia" and once current is flowing the bulb reinforces the current. It would be interesting to see if the shut off voltage is the same as the start up voltage.
I thought about that too. Too lazy to rewrite the program :)
Ive noticed if you have a florescent lamp that flickers as it starts you can make it start much better by shining a light on it as you try and start it.
I have 15w flourescent laps ion each side of my medicine cabinet and in the winter when that room tends to be very cool the tubes have a hard time strting in a cooll room so I usually flip on the overhead light before trying to start those lamps beside the medicine cabinet. Ive also noticed that the starters on those lamps work well when new but soon lose their "punch" and if you take the starter can apart you find the little NE2 type bulb inside the starter has become silvered on the inside.
A couple of years ago i noticed the lamps were getting harder to start so i ordered some starters on ebay and those seemed to start the flourescebt tubes much faster. Out of curiosity I peeled one of these open and found the neon lamp they used was significantly larger (over 1/2" in diameter) than a NE2 (1/4") and looking in the catalogs I can't find anything that looks like the bulbs the Chinese used inside these starters. I suspect these larger neon lamps are just more robust and are not getting slammed by the discharge current.
they are neon but with a bimetallic switch inside.
I just did the same experiment on my flickering neon lamp with a small UV flash light. Yes, it did make it stop flickering. Thanks for very interesting video!
Early models of the HP 110T Spectrum Analyser used a Neon bulb as a 'zener' for 80V. I think in the service manual it lists the use of a special Neon bulb with extra striking power due to radiation. I was always told it was thoriated coating on one of the electrodes but the gas makes more sense.
Spark gaps used to incorporate little dots of radioactive "paint" inside their envelopes to stabilize breakover voltage. I think this is less common now.
The breakdown voltage under a light stimulus depends on the amount of decay of the radioactive material (e.g Kr-85) and hence the age of the bulb. RF energy can extert a similar effect on neon bulbs.
Fun video, thanks.
YOU may be affecting the main experiment, because of the interval between tests : )
Perhaps you could make your script launch 100 tests, alternating, with and without the light. The results could be averaged out. Going further, a photodiode or phototransitor could be used to graph when the lamp lights.
Perhaps some older and cheaper-new neon bulbs may not have the special sauce for easy starting.
At the computer museum, a docent said that one of the vacuum tube computers, such as the ENIAC or something like that--would give different results if the lights were on or not, which would have been quite upsetting.
Brilliant video!!
The light you shine on the lamp ever so slightly raises the temperature of the elements and the gas.
Interesting idea. You could probably get rid of that by placing the bulb on a warming element that would raise it's temperature enough that it would be shedding heat even in the presence of a light. You could also run the experiment without any change of light and see if the heat does create enough free electrons to make a difference. Obviously heat can create free electrons, since that's basically how vacuum tubes work.
Cool. Learned something new
Does the switch stop flickering with candle light?
Is it possible to access your code for this? I’m doing a similar experiment at the moment and i love the feature where you set limits on the voltages you’re reading to narrow down the turn on point!
Radioactive element probably added because manufacturers didn't understand work function or it was cheaper solution. Now, a small % of Ar or H added to help kick off Ne ionization. However, key issue is work function of electrode. Nickel probably used as electrode material with coating of Ba or Sr because they have low work function. Neon bulb becomes flickerish when this coating sublimates. Alkali metals have lower work function, but they have low melting points.
Cool science that visible light can be used to demonstrate photoelectric effect.