I have had first an esl 57 then an esl 63. Being a nerd I did read up on esls. I also recommend Baxandalls chapter as the best info I found.
Apart from a lot of info on esl 57 and 63 it also covers derivation of a equation to calculate the negative electrical compliance, safety margins used and info on how Quad measured it. This is the only place I found this info.
The book is on Safaribooksonline and I think you can have a try period.
/örjan
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You still don't seem to have gotten the function of the 10Meg resistor in combination with the neon bulb.
Once the Membrane has been charged, the neon bulb stops conducting and voltage on the membrane drops steadily, thereby increasing the voltage over the Neon bulb // 47nF.
When this voltage drop becomes ca. 90 Volt, the Neon bulb starts conducting falling back to 40Volt, where the 10Meg limits the current to several uA.
Rapidly the Membrane gets charged and the Neon drops below its sustain level of ca 40Volt and stops conducting.
In a situation at rest, the neon flips on very shortly every 30 seconds.
So when looking on the 47nF parallel to the Neon, you will see a sawtooth.
This means that the voltage on the membrane is never stable, but goes up and down all the time, also while playing music.
Hans
Go back to my post where I used the term "relaxation oscillator".
I understood that back in the early 70's.
You stated it was protection against a short between membrane and stator.
I corrected you on that.
edit: If you are losing that much charge every 60 seconds, you have a problem with your setup. One of the links provided by others detailed how the panels will work for days with the power turned off. You are losing about a volt per second, you won't make it an hour after shutdown.
jn
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FWIW, a neon bulb is at DC pretty much a rough Zener diode, with the "breakdown" voltage around 60-100V. At AC, it looks like a bidirectional Zener, no direct conduction, or as a hollow state diac. As with any diode at breakdown, a resistor is required to limit the current to a safe limit (here 100uA...1mA) past the "breakdown". Neon bulbs ca be used as an AC overvoltage protecton, as a rough voltage stabilizer, or as an AC trigger device.
Neon bulbs do have a negative resistance around the "breakdown" so it is conceivable they could be used as an oscillator, although that would be a very poor one (never seen one myself, designed for this function).
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Did I say otherwise?
I said "as a hollow state diac" and "have a negative resistance".
Attachments
I know what you said. But as a relaxation oscillator, they do not rely on the negative resistance, just on the extinction.
And agreed, they are not good oscillators. Also, the firing voltage is light dependent as well.
john
You cannot build an oscillator without a "negative resistance" (in a generalized sense), one way or another, that would be against the First Principles. For any two port electronic device there is ultimately a negative resistance in the I-V. Check the Gunn diode, diac, tunnel diode, neon bulb. For multiple port electronic devices, the equivalent is a negative differential resistance (that is, dv/di is negative) obtained mostly using (positive) feedback.
So they rely exactly on the negative resistance, even if that's not obvious to you. A short justification is that some sort of power gain is required from such a device, otherwise you could not have anything to oscillate, since the supply energy needs to be converted in the output oscillation energy, otherwise this would be a perpetuum mobile. It is rather easy to prove, using the superposition theorem, that negative resistance devices have some sort of power gain, hence they can oscillate under certain conditions (when the power gain is > 1).
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sheesh, just look up pearson-anson effect. Ya don't need superposition theory to understand the function..the wiki page explains all that one needs to understand a neon bulb relaxation oscillator.
If you want, why don't you fix the wiki page so that the whole world can benefit from your knowledge?
jn
I'm beginning to understand why scientific research takes so long, costs so much and achieves so little. That is presuming that the scientific types that post here are representative of the breed?
My rather successful scientific career (over 100 published papers in peer reviewed journals and conferences, including IEEE, Journal of Applied Physics, etc...) ended abruptly about 25 years ago when I chose corporate money over scientific recognition. Such is life.
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I have not seen that periodic flashing on the Quads I have worked on. In "normal" relative humidity (40% to 60%) the Quads just hold the charge and for a long time. If its discharging there is some leakage somewhere to be addressed. Usually the leakage is accompanied with a ticking sound and soon the need for a new panel. In low humidity (Scandinavia in the winter) the original diaphragms were not working and losing sensitivity so Quad changed the coating at some point.
If the voltage were fluctuating as suggested its 90V in 5200V or 1.8% on the bias. I would be really impressed if you could hear that. . .
Also keep in mind there is a screen on the back side of the panel that is a damping mechanism.
I have had very good success with the rebuilt panels from Electrostatic Solutions ElectroStatic Solutions - Visit
Hans: I read the reviews on the QUAD USA monitor years ago and didn't realise any of those were sold in Europe. Good find!
And less begging for private grants, government grants, etc... Half of the time was paperwork for money hunting, a take no prisoners activity. Add sucking the professors, baby sitting an being sucked by junior wannabees, infinite and totally useless review meetings, activity reports, etc... Perhaps less than 25% was time to focus. Everybody was putting extra after hours to get some relevant results, that nobody really cared about. The only happy times were the visiting teaching exchanges abroad, that was relaxed and rewarding.
They might still have them, I you want I could ask, since then they are working under the name Pentatone.
There were quite a lot ESL’s at that time and nobody wanted them.
Hans
When I would make a list of all the non relevant or dead wrong info you gave on the subject where I tried to correct you, it would become a rather long list. 😀😀
Hans
Thank you, but I really do not have space to fit them in at the moment, or children I can trust (for those who don't know the domestic ESL63 was designed with a fine enough mesh to stop little darlings killing themselves and/or the speakers. The pro version had less concerns over that).
What I didn't know until I just checked was that the pro model was originally spec'd for philips then made into the USA version. Most interesting.
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