There are two ways to solve this problem. 1. Software, but as the author of the topic, there is no software and the possibility of editing it (I I think so), then method number 2 remains. 2. The 4511 chip has a wide power supply range from 3-16 volts. Put the power regulator and turn it up to 4 volts, which will change the output power of the lamp filaments accordingly. Checked more than once.
вторник, 7 марта 2023 г. в 17:02:08 UTC+2, [email protected]: > Martin, > > > > How did you do that? (schematic) > > > > Problem with a pot (or any resistor) is that you would need one for each > element (7 per tube) since you cannot put one in the common line. Each > filament draws about 22mA, so depending on the number displayed, the > current would be anywhere between 44 and 154 mA. This would result in > different voltage drops depending on the number displayed. It would result > in uneven light output. Same reason why you could not use a single current > regulator pre tube, but one per filament would be needed. A voltage > regulator (such as a simple diode) does not have that disadvantage. > > > > Bill v > > > > *From:* [email protected] <[email protected]> *On Behalf > Of *martin martin > *Sent:* Tuesday, March 07, 2023 9:09 AM > *To:* [email protected] > *Subject:* Re: [neonixie-l] Re: IV-9 numitron lifespan > > > > How about this clock I built in the early 80s? 5314 clock chip. I used a > 1k pot for dimming. Has been running for many moons now! > > > > > > > > > > ~ > > *[email protected]* > > > > > > On Tue, Mar 7, 2023 at 5:55 AM gregebert <[email protected]> wrote: > > Under "normal" circumstances, I agree that individual current regulators > add a lot of circuitry. The reality is that most tubes are no longer > manufactured, so their numbers are dwindling as the price increases, > essentially irreplaceable. You wouldn't believe the lengths I went towards > protecting NIMO tubes in the clock I'm still working on. > > > > I've debated about building a numitron clock, and the route I think I will > go with uses LED 'filaments' that are used in retro light bulbs. Filaments > scare the heck out of me because they will fail from thermal cycling, but > there is no alternative for NIMO and VFD displays. > > On Monday, March 6, 2023 at 11:35:22 AM UTC-3 [email protected] wrote: > > Using a current limiter sounds like a LOT of circuitry, 7 times the number > of tubes? I simply use a forward biased diode to drop the voltage, about > 0.7 for a standard silicon diode, and about 0.3 for a Schottky. That > requires only one or perhaps two diodes for the whole set of tubes. Perhaps > not as accurate, but definitely a whole lot simpler. > > > > > > > > > > *From:* [email protected] <[email protected]> *On Behalf > Of *gregebert > *Sent:* Monday, March 06, 2023 8:13 AM > *To:* neonixie-l <[email protected]> > *Subject:* Re: [neonixie-l] Re: IV-9 numitron lifespan > > > > Very good info, Moses. > > > > From that, I would target the operating current well-below 20mA to > prolong the life of the display. You could use an NPN current-limiter > (driver) driven from 5V TTL logic. Let me know if you need circuit details, > but it's a very simple design (1 NPN + 1 emitter resistor). As a starting > point, a 270 ohm emitter resistor will limit current to 16mA. > > > > Do you hear any noise with your PWM running at 1600Hz ? If not, I would > stick with PWM and not use the NPN driver, as it's not necessary. As long > as the PWM cycle-time is shorter than the thermal time-constant of the > filament (probably a few milliseconds), you should be fine. I think you can > measure the thermal time-constant of the filament with a phototransistor > and a scope. Starting at a low PWM frequency, the phototransistor will show > fluctuations in the bulb's intensity. As the frequency is increased, you > should see the amplitude decrease towards zero. I've never actually done > this but I'm pretty sure it will work. You have to use a phototransistor > (or photodiode); a CdS photosensor will have too-slow of a response time. > > On Monday, March 6, 2023 at 2:37:45 AM UTC-3 Moses wrote: > > The TI CD4511B datasheet lists the lists the *minimum* high level output > (at 5v VDD) of 4.1v but typical is 4.55v, maybe others are different? > > > > https://www.ti.com/lit/ds/symlink/cd4511b.pdf > > At 4.55v the segment current on the IV-9 is going to be about 25ma. > Typical IV-9 segment current is about 20ma I believe, so that would be a > 25% overdrive. > > > > I've put up a drive voltage vs segment current table on my site, maybe > it's useful to someone: http://www.neonixie.com/IV-9-6D-RR/#tech > > > > I settled with powering the tubes in my designs in one of two ways.. 5.0v > direct with a recommended PWM of about 65% (the 165 (out of 255) value in > the table) OR 5v through a regular silicon diode, dropping the voltage to > about 4.2v at the tube and PWM that to 76%. Both result in a segment > current of 20ma. Don't know if one or the other is better in regards to > lifetime, I was not able to find any official sources of information. I > experimented with driving them using a 3.3v regulator.. but at that voltage > they were a bit dim. > > > > NOTE: The IV-9 datasheet does mention to avoid running the tubes at a > frequency between 105 and 1000 Hz, presumably to avoid mechanical > resonance. I elected to run them at 1600 Hz. > > > > I looked through some of my testing data.. at a segment current of 3mA the > segments are visible, 2mA they are "barely visible" and at 1mA I noted them > as not visible. Keeping the unlit segments warm with a slight current seems > to make the most sense to me. It's all software on my clock so maybe an > option for the next revision. > > > > That's all I know so far. > > > > Regards, > > -Moses > > On Saturday, March 4, 2023 at 5:52:05 AM UTC-8 [email protected] wrote: > > Hi Chris, > > > > The numitrons are driven by a 4511 decoder, and according to their data > sheets the max. output at that voltage is 4.1 V, so that is well within > specification for the tube. Yes, I agree, lowering the voltage even further > should increase lifespan. > > > > Bill v > > > > *From:* [email protected] <[email protected]> *On Behalf > Of *Chris > *Sent:* Saturday, March 04, 2023 8:19 AM > *To:* neonixie-l <[email protected]> > *Subject:* [neonixie-l] Re: IV-9 numitron lifespan > > > > Hi, > > While i am not sure for the IV9 numitrons have a look at the DA2300 > lifetime expectancy, > > > > Basically reducing the voltage increases the life expectancy > exponentially. > > So i usually run my numitrons at 4.5V or lower and have had no issues so > far. > > On Friday, March 3, 2023 at 8:05:48 PM UTC+1 [email protected] wrote: > > I seem to recall there was some discussion on the life expectancy of IV-9 > numitrons some time ago. > > > > In 2015 I built a number of clocks with these tubes, and they started > failing last year. The clock in the picture is on my bench now, the three > good tubes were replaced in November last year. So today all 6 tubes will > be replaced. I have replaced all 6 tubes on a few other clocks also. One or > more segments will no longer light up, and I do not see any blackening of > the glass tube (The black you see in the picture is my permanent marker, s > I will not replace the wrong tube when I disconnect the power). > > > > The tubes are driven directly from a 4511 chip on a 5V power line. > > > > There does not seem to be any order in which they fail, so I do not have > the feeling that any of the tubes are significantly impacted by thermal > stresses from flashing on and off. I would say based on my experience with > them, the expected lifespan is about 7 years of continues use. > > > > Bill v > > -- > 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 view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/81b5b7e6-d476-4b83-9a8e-c9d6cc468db9n%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/81b5b7e6-d476-4b83-9a8e-c9d6cc468db9n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > 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 view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/13ceb519-9b4d-469e-9e03-8d844e317239n%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/13ceb519-9b4d-469e-9e03-8d844e317239n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > 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 view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/e87e8845-5e21-4b9d-9408-49ee93a3578dn%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/e87e8845-5e21-4b9d-9408-49ee93a3578dn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > 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 view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/CAKYv7NTaviwTXv09wHvzZ3mHt5PFK-5GRSRBArjLtmKp78GekQ%40mail.gmail.com > > <https://groups.google.com/d/msgid/neonixie-l/CAKYv7NTaviwTXv09wHvzZ3mHt5PFK-5GRSRBArjLtmKp78GekQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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