You are right. I think it just acts as a plate in a capacitor, working to increase the surface area for maximum capacitive coupling through the tube envelope.
On Tuesday, October 28, 2014 4:58:49 PM UTC-5, Tidak Ada wrote: > > I am sure! Try it with an Ohm meter. The top is coated and acts as a > electrode. It stands anywhere in the datasheets. I have that tube for > years in my collection. > > eric > > ------------------------------ > *From:* [email protected] <javascript:> [mailto: > [email protected] <javascript:>] *On Behalf Of *Joe Zatarski > *Sent:* dinsdag 28 oktober 2014 22:48 > *To:* [email protected] <javascript:> > *Subject:* Re: [neonixie-l] Re: neon otis elevator 'touch tubes' > > I was not aware of any coating on the tube, and I don't think there's > any connection to the outside of the tube, though I could be wrong. The > Otis docs state that the tubes work on capacitive coupling, through the > tubes envelope. I do not believe any coating on the tube acts as an > electrode. > > On Tuesday, October 28, 2014 4:18:56 PM UTC-5, Tidak Ada wrote: >> >> Is it clear to you all that this tube has a transparent Sn-coating as >> the sensitive electrode? >> Rough handling of the tube surface can destroy it due to disconnection of >> that coating. >> >> eric >> >> ------------------------------ >> *From:* [email protected] [mailto:[email protected]] *On >> Behalf Of *Joe Zatarski >> *Sent:* dinsdag 28 oktober 2014 20:46 >> *To:* [email protected] >> *Subject:* [neonixie-l] Re: neon otis elevator 'touch tubes' >> >> Attached is the schematic in PDF form. All lines except one seem to be >> common between all the tubes. Based on my guess of 135VDC tube supply, I >> think I was right. Tube drops about 72V when on, leaving 63V to be dropped >> by the total series resistance, 3600 ohms. 63V/3600ohm = 17.5mA. This is >> below the maximum rating of 25mA according to the 1C21 datasheet. It then >> looks like an AC supply to the grid would be required to cause the >> capacitive coupling that allows the tube to work as a touch trigger. I'm >> not too sure how to figure out this voltage. >> >> On Friday, October 24, 2014 10:18:34 AM UTC-5, Joe Zatarski wrote: >>> >>> I will draw up a schematic of what I have in the panel now. I think >>> it'll probably be similar to what the otis docs show: resistor connected in >>> series with the tube, trigger and cathode tied together, and connections >>> for B+ and 'B.O.' (B.O. being the reference line for B+, which also happens >>> to NOT be at the same potential as ground, due to the AC supply tied to >>> it). There seems to be a cap, probably in parallel with something, but I'll >>> take a look. >>> >>> On Wednesday, October 22, 2014 4:51:21 PM UTC-5, Dekatron42 wrote: >>>> >>>> I think that the best thing you can do is to ask the company who >>>> replaced it if they can help you with any schematics, otherwise you will >>>> have to draw one yourself from what you have left of the elevator panel >>>> and >>>> we can take it from there, then you will know what voltages you need and >>>> you can do some experiments more easily. >>>> >>>> /Martin >>>> >>>> On Tuesday, 21 October 2014 21:00:47 UTC+2, Joe Zatarski wrote: >>>>> >>>>> I guess now what I would like to know are some example circuits for >>>>> power supplies maybe? I guess I need 135VDC, and it needs to be isolated >>>>> from the mains because it'll also have 150VAC on it relative to earth >>>>> ground. Easiest to do is get a transformer (if I can find the right >>>>> voltage >>>>> output) but how about regulation? Is a properly sized zener diode good >>>>> enough? >>>>> >>>>> On Monday, October 20, 2014 10:41:47 AM UTC-5, Joe Zatarski wrote: >>>>>> >>>>>> So I found an elevator control panel in the garbage. They were >>>>>> replacing a broken one in the dorm next to mine. It appears to have >>>>>> 425A5 >>>>>> 'touch tube' trigger tubes instead of mechanical switches. I saw an old >>>>>> thread here about them which had a bit of info. I think you need to >>>>>> connect >>>>>> a 150vac supply between ground and the cathode, then 135vdc across the >>>>>> anode and cathode to use them as a touch button. There needs to be some >>>>>> resistance in series with the tube of course, and the 135vdc needs to be >>>>>> isolated from the ac. Also, I think the trigger input needs to be tied >>>>>> to >>>>>> the cathode somehow. >>>>>> >>>>>> I still have all the wiring in the panel as it was when I found it. >>>>>> There are 12 floors and a basement, so I'm thinking the buttons can >>>>>> represent the hour of a clock as well as an am/pm light. Furthermore, >>>>>> for >>>>>> setting the time, the tubes can still be used as buttons to type in the >>>>>> time. >>>>>> >>>>>> I'd appreciate if I can get some tips on driving circuitry and >>>>>> supplies since these are cold cathode neon tubes, something I have never >>>>>> dealt with before. >>>>>> >>>>>> -- >> You received this message because you are subscribed to the Google Groups >> "neonixie-l" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/22bc4aa3-28c6-4688-806b-a37a52617d50%40googlegroups.com >> >> <https://groups.google.com/d/msgid/neonixie-l/22bc4aa3-28c6-4688-806b-a37a52617d50%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > To post to this group, send email to [email protected] > <javascript:>. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/0ec3b5bc-57d2-4e98-b964-73c584c567ac%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/0ec3b5bc-57d2-4e98-b964-73c584c567ac%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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