It has been pointed out that a capacitor would NOT be a good substitute for this part, not just for the reasons I listed, but it would cause an AC short as well.
Its probably a poor man's version of a gas-discharge tube for overvoltage protection, in fact I've used neon bulbs for high voltage transient protection.
1. A Capacitor between Telfone Lines would short the SIgnal 2. This Component is likely labeled as something else. In German it is called Gasgefüllter Überspannungsableiter (Gas-Filled Over-Voltage-away-Conductor), while the Neon Bulb is called Glimmlampe (Kindle-Lamp). Think of Zener-Diodes vs Other Diodes. One Optimized for exact Breakdown VOltage, the other for Minimum Breakdown Voltage. 3. Igitors in Classical Flourescent Lamps are also Neon-Bulbs, but with Bimetal Electrodes. They first begin to glow. The warmth bends the lecttodes and shorts them. The SHorting will glow the catholdes of the flourescent tube. Then the Bimetal cools and snaps back. The ending CUrrent causes a Voltage-Spike igniting the pre-heated Flourescent Lamp. Once the FLourescent Lamp Works, the Voltage is too low for the Igniter to glow.
Neon's are a good cheap alternative to gas discharge tubes which can handle much greater surge energy. Once the arc is struck, it will continue to conduct down to a much lower voltage which is good for ensuring the energy is safely dissipated. They were also sometimes used in relaxation oscillators where they are connected across a slowly charging capacitor, and rapidly discharge it when it reaches the striking voltage. The tremolo on guitar amps was sometimes done this way. The purple dot may indicate this is dark effect neon which has a trace amount of radioactive substance added. Without this, and if kept in the dark for a long time, the striking voltage can rise and the neon will no longer function as intended.
It *IS* a neon bulb... the ring voltage is about 90VAC, the approximate firing voltage of a neon bulb. It is used to keep the voltage from getting any higher. Yes I answered before the video finished playing because the title was worded as if you had no idea. A capacitor will not do the job. If it could, a neon bulb would not be in play.
I think the modern substitute is a metal oxide varistor. Metal oxide are widely used today for surge protection devices you would see in a distribution board/panel (at least Europe and UK standards).
Agreed, this serves the same purpose as a MOV (not a capacitor). However, these sorts of neon bulbs are not outdated. They are still used even in lots of modern equipment because they often have the same or better characteristics as a MOV for many applications and can also have a longer lifespan, particularly in situations where their voltage threshold is regularly exceeded.
Not really, since MOV are the slowest over protection device while TVS diodes are the fastest. Though GDTs are in the middle. Though it will also vary depending on the manufacturer.
Transient suppressor. It's an open circuit until a certain voltage level. When that level is i]high enough the gas ignites and shorts out the line. After the transient passes the gas stops conducting and becomes an open circuit again. The gas is probably a mixture to get the triggering voltage correct and might not light up with visible light.
I had forgotten about this Bendix made a series of car radios labeled Sapphire and installed in Volkswagen's back in the 60's & 70's These radios had a Ne2 neon lamp across the antenna and chassis. I heard one once during an advancing storm. As the charge would build and with the radio playing, there would be this screech, building intensity and then fall silent when a flash of lightning would discharge in the sky. It did this several times. I remember building a neon based relaxation oscillator for practicing Morse code back in the 60's
A capacitor would damp the audio. A gas discharge tube aka surge arrester has the advantage that unless it is not triggered it does not affect the signal because it's capacity is just 1pF or so. After it ist ignited by a high voltage spike (e.g. 90 V) the discharge behaves like a short circuit and clamps the voltage to lower voltage until the energy is dissipated to light and heat. After this a the discharge extinguishes and the tube is ready for the next surge. A capacitor would charge up to the peak voltage and keep that voltage unless it is discharged by a resistor, which als would damp the audio signal.
They could probably have used a different component, like say an avalanche diode, but perphaps a neon bulb was a significantly cheaper alternative. en.wikipedia.org/wiki/Avalanche_diode Some sort of relay mechanism might work too, but that probably amounts to unnecessary complexity
0:14 there's not a lot in these... Theres a damned sight more in there than there use to be.. Use to be cradle switch in parallel with dial switch, a speaker, a microphone, a ringer, and a transformer.
@dougaltolan3017 That's true. A lot of viewers were born long after those. I was thinking more of the early electronic phones, before they had specialized components. Not a lot in there, but still more than the newest ones.
@@MiamiMillionaire It put this comment in the spam folder also. You're not using your account for trolling are you? ;) I have some key words on my filter, but they are all swear words and this comment should pass easily. Something else is bothering them.
It has been pointed out that a capacitor would NOT be a good substitute for this part, not just for the reasons I listed, but it would cause an AC short as well.
Its probably a poor man's version of a gas-discharge tube for overvoltage protection, in fact I've used neon bulbs for high voltage transient protection.
Cheapo GDT, yep.
Bang on the money.
1. A Capacitor between Telfone Lines would short the SIgnal
2. This Component is likely labeled as something else. In German it is called Gasgefüllter Überspannungsableiter (Gas-Filled Over-Voltage-away-Conductor), while the Neon Bulb is called Glimmlampe (Kindle-Lamp). Think of Zener-Diodes vs Other Diodes. One Optimized for exact Breakdown VOltage, the other for Minimum Breakdown Voltage.
3. Igitors in Classical Flourescent Lamps are also Neon-Bulbs, but with Bimetal Electrodes. They first begin to glow. The warmth bends the lecttodes and shorts them. The SHorting will glow the catholdes of the flourescent tube. Then the Bimetal cools and snaps back. The ending CUrrent causes a Voltage-Spike igniting the pre-heated Flourescent Lamp. Once the FLourescent Lamp Works, the Voltage is too low for the Igniter to glow.
@@Ribulose15diphosphat I should have said #1above. Danke.
Neon's are a good cheap alternative to gas discharge tubes which can handle much greater surge energy. Once the arc is struck, it will continue to conduct down to a much lower voltage which is good for ensuring the energy is safely dissipated. They were also sometimes used in relaxation oscillators where they are connected across a slowly charging capacitor, and rapidly discharge it when it reaches the striking voltage. The tremolo on guitar amps was sometimes done this way. The purple dot may indicate this is dark effect neon which has a trace amount of radioactive substance added. Without this, and if kept in the dark for a long time, the striking voltage can rise and the neon will no longer function as intended.
@@gadgetwob Interesting information, thank you.
It *IS* a neon bulb... the ring voltage is about 90VAC, the approximate firing voltage of a neon bulb. It is used to keep the voltage from getting any higher.
Yes I answered before the video finished playing because the title was worded as if you had no idea.
A capacitor will not do the job. If it could, a neon bulb would not be in play.
I think the modern substitute is a metal oxide varistor. Metal oxide are widely used today for surge protection devices you would see in a distribution board/panel (at least Europe and UK standards).
I agree, the I/V curve is more like a varistor than a capacitor, especially with the sharp breakdown instead of just filtering
Agreed, this serves the same purpose as a MOV (not a capacitor). However, these sorts of neon bulbs are not outdated. They are still used even in lots of modern equipment because they often have the same or better characteristics as a MOV for many applications and can also have a longer lifespan, particularly in situations where their voltage threshold is regularly exceeded.
Not really, since MOV are the slowest over protection device while TVS diodes are the fastest. Though GDTs are in the middle. Though it will also vary depending on the manufacturer.
Transient suppressor. It's an open circuit until a certain voltage level. When that level is i]high enough the gas ignites and shorts out the line. After the transient passes the gas stops conducting and becomes an open circuit again. The gas is probably a mixture to get the triggering voltage correct and might not light up with visible light.
I had forgotten about this
Bendix made a series of car radios labeled Sapphire and installed in Volkswagen's back in the 60's & 70's
These radios had a Ne2 neon lamp across the antenna and chassis. I heard one once during an advancing storm. As the charge would build and with the radio playing, there would be this screech, building intensity and then fall silent when a flash of lightning would discharge in the sky. It did this several times. I remember building a neon based relaxation oscillator for practicing Morse code back in the 60's
@craignehring Interesting. I was around then but never heard of them. Thanks.
Perhaps the telephone lines would get static electricity on them from the blowing wind, and this piece discharges that?
That beats carrying a piece of sandpaper around .
The second I saw it, brain said neon bulb.
Here in the UK old GPO phones had them.
A capacitor would damp the audio. A gas discharge tube aka surge arrester has the advantage that unless it is not triggered it does not affect the signal because it's capacity is just 1pF or so. After it ist ignited by a high voltage spike (e.g. 90 V) the discharge behaves like a short circuit and clamps the voltage to lower voltage until the energy is dissipated to light and heat. After this a the discharge extinguishes and the tube is ready for the next surge. A capacitor would charge up to the peak voltage and keep that voltage unless it is discharged by a resistor, which als would damp the audio signal.
They could probably have used a different component, like say an avalanche diode, but perphaps a neon bulb was a significantly cheaper alternative.
en.wikipedia.org/wiki/Avalanche_diode
Some sort of relay mechanism might work too, but that probably amounts to unnecessary complexity
'Gas arrestor'
0:14 there's not a lot in these...
Theres a damned sight more in there than there use to be..
Use to be cradle switch in parallel with dial switch, a speaker, a microphone, a ringer, and a transformer.
@dougaltolan3017 That's true. A lot of viewers were born long after those. I was thinking more of the early electronic phones, before they had specialized components. Not a lot in there, but still more than the newest ones.
Chevy Caprice, yeah!
Compare it to a DIAC instead of a capacitor.
Not sure but it could be part of the ringer circuit....plug it in and call it to make it ring and see if the bulb lights.
It's there to protect against surges from lightning strikes on the overhead wires.
I have a Transparent one from the 80s wich is full of them
Strange, RUclips put your comment in the spam folder.
@@tsbrownie The censorship thing is getting completely out of control 🤦
@@MiamiMillionaire It put this comment in the spam folder also. You're not using your account for trolling are you? ;) I have some key words on my filter, but they are all swear words and this comment should pass easily. Something else is bothering them.