I just took another look at the schematic you provided, you're right.
You don't need to do cathode side blanking. For some reason, I thought
that you had both nixies in the pair connected to the same 74141 and
would need to blank cathode side in order to address a single nixie.
Since you have e
Indeed, I see you got it right :)
Anyhow, I got it all fixed. I just lowered the power supply to 180V.
Of course, I had to recalculate all the anode resistors (finally have
individal anode resistors), but the blanking now works just fine.
But still, I don't understand why I should blank one nixie i
On Friday, 16 March 2012 19:22:05 UTC, Imbanon wrote:
>
> Oh and I accidentaly reported your post as spam. Sorry about that!
> Dunno how that effects anything though..
>
It doesn't - the mods clean up behind you ;-)
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On Thursday, March 22, 2012 11:12:21 AM UTC-7, Adam Jacobs wrote:
>
> The resistor between the base of the PNP and the collector of the PNP
> should be more like 10k.
>
>
> More like between base and emitter, to speed up turn-off time.
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It's an interesting combination those 2 npn transistors. The signal on
the base is actually inverted compared to "normal" npn/pnp
transistors. When T2, T3, T5 are switched off, the tubes are actually
on :-). That's also where your leakage problem comes from if you ask
me. You choose 220k resistors,
Ok, Good luck.
On 3/22/2012 12:05 PM, Imbanon wrote:
Why would you say something like that? What's wrong with using
trimpots instead of resistors when you're not home with your stuff? Or
using NPN based anode drivers.. Why would I NEED to make a so popular
NPN-PNP anode driver, when I first thou
Why would you say something like that? What's wrong with using
trimpots instead of resistors when you're not home with your stuff? Or
using NPN based anode drivers.. Why would I NEED to make a so popular
NPN-PNP anode driver, when I first thought of something like this,
with parts I already had. An
I'm starting to get the impression that this is a parts-box project.
Have you ever heard the expression that when the only tool you have is a
hammer, everything starts looking like a nail?
On 3/22/2012 11:42 AM, Imbanon wrote:
Please take note that I am not using PNP's at all, only NPN's :)
O
Please take note that I am not using PNP's at all, only NPN's :)
On Mar 22, 7:12 pm, Adam Jacobs wrote:
> _MUCH_ better.
>
> Okay, firstly this design can work - there's nothing fundamentally wrong
> with it. Like I said, you'll need to be able to make cathode-side
> blanking (74141) work if you'
_MUCH_ better.
Okay, firstly this design can work - there's nothing fundamentally wrong
with it. Like I said, you'll need to be able to make cathode-side
blanking (74141) work if you're going to stick with only 3 anode drivers.
1) Your anode drivers aren't quite right. The resistor on the bas
Sorry about that. I thought it was an universal shematic file type,
'cause they are all .sch
Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729
Cheers
On Mar 22, 4:14 pm, Adam Jacobs wrote:
> Would you mind converting that schematic to some kind of image file? Is
> that an ea
Would you mind converting that schematic to some kind of image file? Is
that an eaglecad file?
blanking on the 74141 will cause leakage if the supply voltage is too
high. Are you using real 74141's or the russian kind?
From that picture, I'm not sure if that is leakage.
-Adam
On 3/22/2012 5:
Could you share a few pics? Also, how much will they cost? :)
On Mar 19, 2:33 am, Cobra007 wrote:
> That should be fine Adam, I should have 50 modules in a couple of
> weeks so I do have a few spares :-).
>
> Michel
>
> On Mar 19, 11:31 am, Adam Jacobs wrote:
>
>
>
>
>
>
>
> > I would be interes
Hey all
I found some time to make a schematic. It only shows the two 74141,
nixie tubes and anode drivers.
I also tried blanking nixies via 74141. I would have never guessed
that you meant on hex code, as I am doing this on an arduino :)
Blanking nixies with 74141's give me a lot of leaking (or at
That should be fine Adam, I should have 50 modules in a couple of
weeks so I do have a few spares :-).
Michel
On Mar 19, 11:31 am, Adam Jacobs wrote:
> I would be interested in this as well. Are you planning to market and
> sell these modules?
>
> On 3/18/2012 4:19 PM, Cobra007 wrote:
>
>
>
>
I would be interested in this as well. Are you planning to market and
sell these modules?
On 3/18/2012 4:19 PM, Cobra007 wrote:
Hi Dylan,
It is actually a small circuit board that I have manufactured together
with the nixie watch circuit boards to save costs. The circuit board
is the size of a
Hi Dylan,
It is actually a small circuit board that I have manufactured together
with the nixie watch circuit boards to save costs. The circuit board
is the size of a DIP24 chip and has an SMD 4514 multiplexer that
drives 10 high voltage SMD mosfets. There is 1 spare mosfet on the
board that is no
I'm very interested in hearing more about this module...Are you saying you
are having this custom manufactured? If so, how have you found a way to do
this economically?
On Sun, Mar 18, 2012 at 6:31 PM, Cobra007 wrote:
>
>
> For my clock I am designing a module as I am not really a fan to use
> t
I'd start with 6.8K anode resistors (assuming 3,6 to 7.3 is your target
range) and see how it works out. Keep a close eye on it for a couple of
months, if its running 24/7. If the current is too low, you'll start to see
partial illumination on the the digits over time. Then you need to increase
If you take 7.3k resistors rather than 3.65k resistors, the tubes will
only be 6dB less bright which is not significant. If that increases
tube life, I would say, that is the better choice as you pointed out
already.
For blanking, I think Adam means to send a hex number (0x0A) to the
74141 (D=1; C
Hey Cobra! Thanks you for your explanation. I see what you did there,
and you are quite correct. But the thing is that I did not calculate
anything using power. You are completely right with the brightness,
but I do not want the same brightness as with direct drived nixies. I
lean towards tube life
Hi Imbanon,
I followed your calculations for quite a bit and was also wondering
why your measurements are so much different than your calculations. My
calculation suggest that you need a 7.3k resistor for each tube. This
means if you have 2 tubes with a common anode connected to 1 resistor,
and sw
I wasn't home at the time, and all I had were three 10k trimpots :)
Why is that bad? I would leave it that way, if that's ok.
On Mar 16, 8:27 pm, Adam Jacobs wrote:
> Why are you sharing 1 anode resistor across two tubes? :) Is board space
> at that much of a premium?
>
> On 3/16/2012 12:18 PM, I
Why are you sharing 1 anode resistor across two tubes? :) Is board space
at that much of a premium?
On 3/16/2012 12:18 PM, Imbanon wrote:
First of all, thank you all for your support. Feels great to have some
people with knowledge behind my back.
So many replies since I had time to check the gr
Oh and I accidentaly reported your post as spam. Sorry about that!
Dunno how that effects anything though..
On Mar 16, 9:13 am, Dekatron42 wrote:
> Many manufacturers write that you will have to contact them for the
> special curves you need when you are going to multiplex their Nixies
> since th
First of all, thank you all for your support. Feels great to have some
people with knowledge behind my back.
So many replies since I had time to check the group last time that I
don't know where to start :)
I do not have a schematic for my design, as it is my own design that I
pretty much pull out
> What would the reason be to choose for a higher voltage rather than a
> lower anode resistor? You can achieve a higher tube current by either
> raising the voltage or lowering the resistor, so what is the advantage
> of raising the voltage? Is it because ionization will be quicker or
> doesn't ha
It all has to do with how you design the circuit around the Nixie, in
the old days the transistors did not have perhaps more than 120V Vce
as a maximum, usually lower than that, around 80-100V. With a lower
Vce you have to use either a cathode bias voltage to meet the
transistor requirements or you
That makes sense indeed.
What would the reason be to choose for a higher voltage rather than a
lower anode resistor? You can achieve a higher tube current by either
raising the voltage or lowering the resistor, so what is the advantage
of raising the voltage? Is it because ionization will be quick
Many manufacturers write that you will have to contact them for the
special curves you need when you are going to multiplex their Nixies
since they do not usually print that information in the databooks.
These sheets show you that the Nixie will have an increased turn-on
voltage corresponding to t
Yes, I think I mentioned "slightly" increase rather than a mayor
increase.
I have measure this on another nixie tube and came to the following
voltages:
0.5mA : 120V
1.0mA : 125V
1.5mA: 130V
2.0mA: 133V
3.0mA: 140V
4.5mA: 150V
His tube current will increase from 2mA to about 7.5mA, so according
t
On 12-03-15 05:46 AM, Cobra007 wrote:
So it looks like your resistor is correct. The only thing is that the
voltage across the tube will slightly increase due to the higher
current, so it's not 100% correct but pretty much.
Since we are talking a Neon device, the voltage across the tube will t
Interestingly, I just realize, if you work this further out you come
to the following formula:
Rmux = Rdc * (T1/T)
Rdc is the anode resistor in direct drive (55V / 2mA = 27.5k)
Rmux is the anode resistor in a multiplexed system = 27.5k * 0.267 =
7.3k :-)
Michel
--
You received this message bec
not mistaken. For a
> > > > mainly
> > > > troubleshooting tool (citation needed), that is not a bad choice. After
> > > > all,
> > > > many AC signals
> > > > found in circuits have a DC offset. Assuming sinewaves makes the design
>
DMM that is TRUE RMS. Nice
to have
that AC/DC switch though, on the Tek meters. But I m still a Fluke only guy
;-)
Frank
From: Nick
Sent: Tuesday, March 06, 2012 4:03 PM
To: neonixie-l@googlegroups.com
Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
Yes, RMS has only on
t
> > >>> it's better than nothing!
> > >>> Check it out and tell me what you think.
> > >>> Also, the supply is set to 200V. It that too
> > >>> much?http://youtu.be/p7QNEL8s4l4
> > >>> Thanks everyone
> > &g
mistaken. For a
> >>>> mainly
> >>>> troubleshooting tool (citation needed), that is not a bad choice. After
> >>>> all,
> >>>> many AC signals
> >>>> found in circuits have a DC offset. Assuming sinewaves makes the design
&
M that is TRUE RMS. Nice
to have
that AC/DC switch though, on the Tek meters. But I’m still a Fluke only guy
;-)
Frank
From: Nick
Sent: Tuesday, March 06, 2012 4:03 PM
To: neonixie-l@googlegroups.com
Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
Yes, RMS has only one physic
No, it is still not correct because the total power consumption
doesn't add up.
The 12mA DC current for the 200V supply is correct because you want
2mA for each tube.
This means when multiplexing, a pair of tubes must have a maximum peak
current of 12mA, not 6mA. That's where the problem is.
12m
I can smell a misunderstanding here (from my side, that is).
What are you trying to achieve? I just read your previous posts, it
seems like you're after 2mA average current per tube, so your power
supply should be able to deliver 12mA in total.
I assume the anodes from the 2 tubes go through 1 re
e. After
> > > all,
> > > many AC signals
> > > found in circuits have a DC offset. Assuming sinewaves makes the design of
> > > the meter
> > > easier (cheaper).
>
> > > I would not expect a different behaviour from a DMM that is TRUE RM
gt; easier (cheaper).
>
> > I would not expect a different behaviour from a DMM that is TRUE RMS. Nice
> > to have
> > that AC/DC switch though, on the Tek meters. But I’m still a Fluke only guy
> > ;-)
>
> > Frank
>
> > From: Nick
> > Sent: Tuesday
>
> From: Nick
> Sent: Tuesday, March 06, 2012 4:03 PM
> To: neonixie-l@googlegroups.com
> Subject: [neonixie-l] Re: Calculating multiplexed nixie's RMS current
>
> Yes, RMS has only one physical definition, but in the case of DMMs the
> actual implementation is obfuscated.
>
>
expect a different behaviour from a DMM that is TRUE RMS. Nice
to have
that AC/DC switch though, on the Tek meters. But I’m still a Fluke only guy
;-)
Frank
From: Nick
Sent: Tuesday, March 06, 2012 4:03 PM
To: neonixie-l@googlegroups.com
Subject: [neonixie-l] Re: Calculating multiplexed nixie'
Actually the signal was applied to a "thermocouple" which was "one
arm" of a bridge circuit. An "identical" thermocouple, which was a
"second arm" in the same bridge circuit, then had D.C. applied to it. A
null was then achieved across the bridge, and the meter actually
measured the D.C.
Yes, RMS has only one physical definition, but in the case of DMMs the
actual implementation is obfuscated.
"true" RMS in a DMM context is an RMS calculation that does not assume a
sine wave - most cheaper DMMs do indeed assume a sine wave input.
Then there are "true RMS" (and indeed "ordinary"
Actually there is only a definition of RMS, not subject to
"trueness" :)
http://en.wikipedia.org/wiki/Root_mean_square
AFAIK, the old instruments that gave a true-"true RMS" output measured
the heat generated by the signal when applied to a resistor. That way
the waveform shape did not affect the
On Monday, March 5, 2012 8:46:42 AM UTC, Cobra007 wrote:
>
> Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't
> expect that to be honest as it undermines the definition of "true RMS"
> but a simple battery test shows 0V RMS :-).
Its not a commonly known problem, even among pro
Yes, you're right Nick, the Fluke is indeed AC coupled. I didn't
expect that to be honest as it undermines the definition of "true RMS"
but a simple battery test shows 0V RMS :-).
Michel
On Mar 5, 6:08 pm, Nick wrote:
> Digital MMs sample and require a periodic waveform to give accurate resu
Digital MMs sample and require a periodic waveform to give accurate results
- even so-called "true RMS" DMMs do this. The whole business of what
constitutes a "true RMS" reading is beyond the scope of this note - e.g.
how is any super-imposed DC level incorporated in the calculation - most
so-c
If you direct drive them @ 12mA and you want to have them the same
brightness when multiplexed, you will need to increase the current to
36mA (as they are only on for 1/3 of the time). Which means 12mA for 2
tubes at all times, 6mA per tube @ 33% duty = 2mA average current per
tube.
Adam is right,
I direct drived all 6 of them, delivering 12mA without a problem.
Tested only up to 15mA. Didn't want to go further..
Thanks again
On Mar 4, 11:29 pm, Adam Jacobs wrote:
> Disable the multiplexing, so that only 2 nixies are lit (and those lit
> at 100% duty cycle). THEN measure the current draw.
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