I keep on accidentally saying these tubes are 72V, everytime I say that, change it to 71V...
On Wednesday, October 29, 2014 12:42:05 PM UTC-5, Joe Zatarski wrote: > > I tried it out. It's running off of 200VDC from inside a TV with some > extra resistance in between. Using 200V - 72V (the rating of my tubes) I > get 128V, and I have the original 3600ohms plus another 3500 in series, > giving 7100 ohms. All that results in about 18mA of current through the > tube. I even get a bit of touch sensitivity when the TV is just starting > up, due to AC bleeding through past the regulators I guess. Otherwise, I > can tie the trigger input to the 200V (which has that 1.5Mohm resistor in > series) and start it that way. > > On Tuesday, October 28, 2014 2:45:57 PM UTC-5, Joe Zatarski wrote: >> >> 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 an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/69d9ef51-8364-4588-9628-00c1491c16a3%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
