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"DanielK" <kuriloff@...> wrote:

Can anyone tell me if the CD4511 can drive B7971 Nixie tubes
directly or must I have each tube segment driven in addition
with mpsa 42 HV transistors?

I basically want to use the CD4511 in place of the DS8880 HV
BCD-to-7 Segment decoder ...

Dan

No, a CD4511 can't drive a nixie (B7971 or any other) directly. You need to add those HV xstrs (MPSA42), with 42 base resistors (22K ea). You can substitute some old fashion SN75468 relay/lamp drivers, for the HV transistors. One SN75468 will replace 7 MPSA42 xstrs, and 7 22K resistors. However, you may need to add a mid-pull circuit. Use an resistor divider to make a voltage around 80V. Tie that to the pin on the SN75468, that's common to all its protection diodes (pin 9). This will keep the cathode from exceeding the 100V rating of the SN75468.

Lovely little gadget, that meter is.

Instead of buying a meter, how about making your own, 'old fashion' style LCR bridge, with a magic eye tube (to keep it somewhat on topic):



That will be a nice 'retro' project (for an inductance bridge).

Its comprised of a 1KHz oscillator, that feeds the same signal to two sides of a bridge (a divider per side). One side is a resistor and a pot. The other side is a set of reference inductors (switch selectable for range), and a the spot where the unknown component plugs in. When the ratio of both sides are equal, both the amplitude and phase, of the signals at both divider taps will be equal. Both of those signals can be fed to a differential amp, made from one dual triode (6J6, 12AT7, 12AX7 ...). The AC output when both signals match is zero. Rectify (6AL5) and filter that signal, then feed it to the (pre-biased) triode section of the magic eye (6E5, 1629, EM80, EM84, ...) and then feed that signal to the eye control itself, and there you have it. The eye's shadow should be smallest, when pot/resistor ratio matches the inductor side. You can use some known values for making a calibrated dial, for the pot.

I am using a Stamp to drive the binary pins on a 74141, I have the 74141 powered with +5V, and ground. I know my code is good (tested with LEDs, all checks out, the binary adds up and is timed perfectly.
Something is not working. I have the HV coming from a Tayloredge HVPS, with a 15k on the anode. I have tried four different 74141 (both American, and Russian) Nada. I watched long enough, and the 6 will light up, but nothing else. It lights when it is supposed to, in sequence, but nothing else. I have tried four tubes as well.
the notch at the top of the 74141 is between pins ONE, and SIXTEEN right? What am I missing here?
Thanks
Shane

Besides my single-board IN17-based 7 digit, I did a HH:MM:SS:T display board with 8422s and one IN17 for tenths; This board is compatible with the same board I am working on.



I also have a B7971x4 board and an IN18x4 board; 2 can be chained for 8 B7971s.

You can keep up with the progress by subscribing via rss or provide feedback via google groups link at the top of this page.



Cheers,
..c

--- In NEONIXIE-L@..., "jonellis32" <jon@...> wrote:

this thing detects which and quantifies the value with one button push. A very smart time saver.

Lovely little gadget, that meter is. Matter of factly, I love instruments in general, and how they are able to decypher things. One of my favorites is my digital caliper and I love to try to trick it - by setting it to zero, work with it a bit and slowly bring it back to the starting point. Amazingly enough, it goes nonchalantly back to zero, and if I put a mere piece of plastic film there, the sucker still shows 0.01. I have no idea where it gets its precision from, what type of component can measure such a small movement. Anyone knows what's in there? I once read it is based on capacitance.

I also love to think of precision (and tolerances, for that matter) as a concept, almost as a value in itself, and find myself looking at everyday objects and trying to find the type of precision bourne in them.


[And I completely agree with Mr. ThreeNeurons (but, boy, WHAT three neurons...) that your gray matter is the best equipment you can make use of.]

--- In NEONIXIE-L@..., David Forbes <dforbes@...> wrote:

The 224 is indeed 22 followed by four zeroes, or 220,000 of whatever unit the
manufacturer decided to label the part with. Often that's nanoHenries.

A coil with some number of uH is usually about the size of your fingertip and
has many turns of wire, but the wire is big enough to see. These are used in
switching power supplies at some hundreds of kHz. This is what you have, right?

That's right, Dave, I've got my metric conversion mixed up, sheesh. 220,000 nH - not pH - amounts to 220 uH. On the other hand, the "224" inductor is indeed the size of a fingertip (the 'pinkie', precisely :) and it is functional on the said equipment, so no way it could work if it was off 1000 times from the specs.

I "still" want the one for B7971 6,7,or 8 tube (So, 2x chained)

Michail

On 8/2/2010 1:36 PM, cagamba wrote:

Howdy. Here's a basic question about the labeling of inductors ...

Thanks

Marco

Marco,

The 224 is indeed 22 followed by four zeroes, or 220,000 of whatever unit the manufacturer decided to label the part with. Often that's nanoHenries.

You can tell at a glance which of nH (nanoHenries), uH (microHenries) or mH (milliHenries) a coil is by the number of turns and the wire diameter.

A coil with some number of nH is wound with just a few turns of wire. These are used at radio frequencies, over 30 MHz typically.

A coil with some number of uH is usually about the size of your fingertip and has many turns of wire, but the wire is big enough to see. These are used in switching power supplies at some hundreds of kHz. This is what you have, right?

A coil with a large number of mH is bigger than your thumb, and/or is wound with so many turns of fine wire that you can't see the wires individually. These are used at audio frequencies, such as speaker crossovers or telephone signal coils.

--
David Forbes, Tucson, AZ

--- In NEONIXIE-L@..., "threeneurons" <threeneurons@...> wrote:

I know a lot of people don't want to be bothered doing it the long way, but you'll learn something. A basic understanding of electricity, will often get you out of a bind. Understanding the 'fundamentals' (in any field) is worth a lot more than any fancy piece of equipment.

Totally agree - your brain is the best test instrument you'll ever have. But if you want the fancy piece of equipment route, then get yourself one of these:



Animal, vegetable or mineral, this thing detects which and quantifies the value with one button push. A very smart time saver.

Cheers,

Jon.

PS No connection with the company beyond serial happy purchaser.

One of the best investments I have made into my test bench was buying
an LC-meter. I got a relatively cheap one off eBay, I paid €40.21 for
the device (free shipping), and am just happy about the meter I
bought. The model is DM4070.

Not that I'd discourage trying to decipher the component labeling,
however, sometimes the labels are so cryptic that using a meter is
much faster than endless googling.

Or, if you don't have a RLC bridge you can do what I have done to
measure hand wound coils. I use my function generator to drive a
circuit at a known frequency and set up a voltage divider with the
coil. Size the resistor appropriately for the drive capability of your
function generator. Also, remember that a meter is typically 10MOhm,
so if you limit the current with a 1MOhm or greater resistor, the
meter is going to noticeably alter the measurement.

If you don't have a function generator, you could use a low voltage
transformer and work from your supply frequency (50 or 60Hz). Use
Ohm's law and the reactance formula to get your value of L.

XsubL (inductive reactance) = 2*pi*f*L OR
L = XsubL / (2*pi*f)

Where XsubL = E/I

Howdy. Here's a basic question about the labeling of inductors ...

Thanks

Marco

Depends largely on the manufacturer. For a 220uh inductor, you'll commonly find it labeled 221 or 224, for 'uh' or 'nh', respectively. See if you can make out the maker of the part, and refer to their datasheets. If you can't, then get hold of an LCR bridge or meter. If neither of these are an option, you can always learn a little basic electricity, and rig your own simple bridge.

The calculation for inductive reactance (Xl) is Xl=2*pi*f*L, where Xl will be in units of ohms. Make a simple divider, using a small trimpot of 5K ohms, hook it up in series (tap to one side) with the unknown inductor. Feed a 1MHz signal to that divider. measure the voltage drop across each component, individually. Repeat while adjusting the trimpot, until the voltages are equal. Turn off the rig, and measure the DC resistance of the trimpot (tap to the side used above; tap aka wiper). That DC resistance will match the reactance of the coil at 1MHz. The 1MHz source, can be made using a logic inverter (7404, 74HC04 ...), a 1MHz xtal (crystal), and a pair of small caps, and a resistor (2M2 to 10M). You can google 'simple crystal oscillator', for the schematic. For a 220uh coil the reactance will be in the 1300 ohm area. If its under a couple of ohms, then its 220nh (nano-henries). It won't give you precise measurements, but at least you'll be in the 'ballpark'.

I know a lot of people don't want to be bothered doing it the long way, but you'll learn something. A basic understanding of electricity, will often get you out of a bind. Understanding the 'fundamentals' (in any field) is worth a lot more than any fancy piece of equipment.

On Mon, Aug 2, 2010 at 11:36 PM, cagamba <cagamba@...> wrote:

Howdy. Here's a basic question about the labeling of inductors (those that resemble small electrolytic capacitors), commonly used in switching power supplies. I searched the web on the answer to this but found no specific answer on inductors, only for capacitors.

Hello,

I understand that I'm not answering your question, however, I believe
my comment is relevant.

One of the best investments I have made into my test bench was buying
an LC-meter. I got a relatively cheap one off eBay, I paid €40.21 for
the device (free shipping), and am just happy about the meter I
bought. The model is DM4070.

Not that I'd discourage trying to decipher the component labeling,
however, sometimes the labels are so cryptic that using a meter is
much faster than endless googling.

BR,
Dmitri

Howdy. Here's a basic question about the labeling of inductors (those that resemble small electrolytic capacitors), commonly used in switching power supplies. I searched the web on the answer to this but found no specific answer on inductors, only for capacitors.

Here's the situation, I have some lose inductors which are labeled 224C and I can't figure out their micro-Henry reading just by looking at that code.

Inductors labeled as such are present in circuits I have at hand (RW's 4LW and GeekKlok) and their schematics call for 220 uH (micro-Henry) parts, so I wonder if that's the correct inductor to be there in the first place.

The schematics of other circuits I have (standalone switching power supply, for instance) also call for inductors with a 220 uH reading, and the one actually installed in the unit is labeled 221 (which, borrowing from capacitors, I suppose could mean "22 and 1 zero", bringing it to 220, while uH would be the unit of choice).

But the labeling on the 224C inductor puzzles me a bit. Could it be that it means "22 plus four zeroes" - 220 thousand ***pico-Henries*** (which equals 220 micro-Henries)? If so, how to avoid this kind of confusion in the units used?

Thanks

Marco

--- In NEONIXIE-L@..., Dmitri Vorobiev <dmitri.vorobiev@...> wrote:

I think this still may be interesting for the subscribers.

So, if there the moderators would not mind that, please continue here.

So I don't bog my own thread down, I've PM'd Nick to ask about some preliminary design questions. Since there appears to be some interest, I'll make sure to update the thread as I get further along.

Nixies offer interesting ideas for low-power audio design, so it'll be interesting to see if I can get the EMI under control and the power rail suitably filtered for audio use.

I like single and twin tube clocks. Rows of tubes doing
very little except sitting there glowing orange don't do
it for me. I want movement. ...

Cosmic. Personally I'd rather watch a bagel go stale. A nixie
tube that does nothing is just a neon lamp. You owe it to them
to do more than that.

John S

That's why I like Dekatrons:

A standard 7 segment tube representation like a Russian IV-12 VFD, for example, displays a single center segment to form a block digits 2,3,4,5,8,9

-- Now imagine that same numbers on the 7971 which, because of it's additional segments, requires segments 14 and 16 be energized simultaneously (or a total of 8 segments) to form that same `8'. But you only have 7 outputs from 4511 or DS 8880 BCD-to-seven segment decoder drivers. Do I short those 2 segments? Also how do I calculate the correct cathode resistor value for the shorted segments relative to a full horizontal segment to get the same brightness level?

Can anyone tell me if the CD4511 can drive B7971 Nixie tubes directly or must I have each tube segment driven in addition with mpsa 42 HV transistors?

I basically want to use the CD4511 in place of the DS8880 HV BCD-to-7 Segment decoder driver to replace the 74141 BCD-to-decimal HV decoder driver used in the Moses microcontroller for his 6 digit clocks. I would have used the DS8880 drivers I already have but Moses uses a BCD output of 1111 or HHHH to do all of his leading zero blanking, PWM dimming, cross fade and timed display off routines.

All of the data sheets are uploaded in the files section here.

"DIGIT BLANKING
By default the controller `blanks' digits by outputting all ones on the BCD lines. Blanking is required for PWM dimming,leading zero blanking and cross-fading to work properly. This default setting works well with 74141 Nixie Driver ICs, but if you are using other display drivers you might want to review the Digit Blanking option (#53). For example if you are
using the controller as a simple LED binary clock, you would want to set this option to either 3 or 4. This will result in a low output on the BCD lines during dimming, correct for individual LEDs. A separate blanking output pin is also provided (pin 27), which can be used for dimming display drivers with separate blanking inputs. It can be set for low or high blanking. NOTE: If using the blanking output pin of the controller wired to all the displays, the clock will not cross-fade or blank a leading zero properly since each digit needs its own blanking output. A simple solution is to hook up a NAND gate (for
drivers with low blanking inputs) or a AND gate (for drivers with high blanking inputs) to the C and D connection of each BCD output (with BCD blanking set to high). Run the output of the gate to the digits blanking input. This works because
BCD C and D will only be high when the controller commands a blank digit.
NOTE: If you will be using the blanking pin, it is recommended to install a 3-way jumper in order to disconnect the drivers from the blanking output and connect them to a logic level that will result in an active display. This can be used in
case the digit blanking option is accidentally modified to blank the display.

When comparing the truth tables between the 74141 and the DM8880N if 1111 or HHHH as implemented by Moses to blank the display for his 6-digit controller I think the digit "F" would be displayed instead of a blanked tube. So I don't think I can use the DM8880N for this purpose, hence the suggestion to use the CD4511.

I am not sure I understand what Moses means about use of the #53 option or the NAND or AND gate solution. I am not sure either of these suggestions would help me get the controller to work properly with the DM8880N and hence the CD4511 suggested by WESTDAVE.

Any clarification here would be much appreciated.

You can email me directed off the listserve for more discussion if you like .....

kuriloff@....

Dan

--- In NEONIXIE-L@..., Quixotic Nixotic <nixotic1@...> wrote:
...

"Ethel, if you watch this left hand tube for the next ten hours,
you'll see it does this really neat fade for a second, going between
1 and 2. No wait, don't go, really it does."

Cosmic. Personally I'd rather watch a bagel go stale. A nixie tube
that does nothing is just a neon lamp. You owe it to them to do more
than that.

John,

As usual, I find myself agreeing with you!

One of the big plus factors of two digit clocks is not having to worry about cathode poisoning, not to mention more usable shelf space...

Nick

Just one of many futures for me:



--
David Forbes, Tucson AZ

--- In NEONIXIE-L@..., Quixotic Nixotic <nixotic1@...> wrote:

On 1 Aug 2010, at 00:44, figureloop wrote:

I'm inclining toward making some future Nixie clock designs...

Recycled joke: "Did you hear they are putting a nixie clock in the
leaning tower of Pisa? So it can have the time as well as the
inclination - but in neon this time."

I like single and twin tube clocks. Rows of tubes doing very little
except sitting there glowing orange don't do it for me. I want
movement. One and two tube clocks allow this. But six or more tube
clocks?

"Ethel, if you watch this left hand tube for the next ten hours,
you'll see it does this really neat fade for a second, going between
1 and 2. No wait, don't go, really it does."

Cosmic. Personally I'd rather watch a bagel go stale. A nixie tube
that does nothing is just a neon lamp. You owe it to them to do more
than that.

For me my HH is also my MM and my SS,

John S

Interesting to actually hear someone articulate a good reason for liking single digit clocks.

I understand your perspective, but I want to see the time with a quick glance. So I don't mind if the slow tubes are just sitting there for hours not changing.

Fading is a cute trick, but not essential. I may implement in in the future, but probably with an option to enable it or not.