开云体育

Anyone here ever pursued building a Penta device (by Giampaolo Minetti), the one portrayed in Neonixie's opening picture?

I believe it would work well with Portuguese, which has very interesting (ahem) five letter words. I also find its "industrial" look, using five ZM 1350, very cool.

I've tried contacting him a few times, only received a response once, more than one year ago, he was a bit busy at the time due to health issues from a relative, if I remember correctly.

He was kind enough to provide a vast array of information on his page,



but the page itself seems to be derelict these days and it falls short of providing a list of parts (no big deal, actually) and of mentioning any improvements from the original design, so I wonder if it is a viable project.

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

Anyone here ever pursued building a Penta device (by Giampaolo Minetti), the one portrayed in Neonixie's opening picture?

I believe it would work well with Portuguese, which has very interesting (ahem) five letter words. I also find its "industrial" look, using five ZM 1350, very cool.

I've tried contacting him a few times, only received a response once, more than one year ago, he was a bit busy at the time due to health issues from a relative, if I remember correctly.

He was kind enough to provide a vast array of information on his page,



but the page itself seems to be derelict these days and it falls short of providing a list of parts (no big deal, actually) and of mentioning any improvements from the original design, so I wonder if it is a viable project.

Hello,
I am the author of the Penta device. I see that Marco (cagamba) has posted a message about it, and I feel I should give an answer. It is true that I did not have time to answer personal email last year and part of this year too, for personal problems. I am 47, unmarried, a biochmist and teacher at the university of Pavia, Itly. This is my full time job and when I say full-time I remember one of those Murphy's laws that says something like "Biochemistry expands to fill all the time and space available". This is the second reason why I am not very active in the group and in keeping in touch with those who contact me privately. Sorry.
I have always had a deep passion for electronics, since I was 12-13, that started bordering on the verge of insanity once a nixie tube made its first appearance in my house. I still remember my father bringing home one lonely specimen, a horizontal-view ZM1186 I believe, with red filter and a nice socket. It was then a matter to figure out how to make it glow, but that came later, after having learned how to assemble digital counters around 7490 decades, 7475 latches and display drivers. This was fun in those years, when digital IC's started becoming available to the experimenter. Apart from the various electrocutions I experienced with high voltage sections, I remember blowing the whole series of 7490 decades, latches and 7441 drivers in what was intended to be a frequency meter, when I inverted the polarity in the 5V power supply. Those 7490 cost each the equivalent of perhaps 15 Euro of today, which was maybe twice my weekly allowance as a kid. I am sure many in the group that are my age know what I am talking about.

Anyway, the Penta project. Despite the all-pervading professional engagement, I did find some time a few years ago, I don't know how, to build it. It was, it is, and it will remain (I think), a proof of principle that those displays could be driven with a small microcontroller, and for the fun of displaying words and time of the day.
The project is not stalling neither developing, it is out there for others to play with, since the code is available, the schematics is not very complex and it works, and I intend to come back to it as soon as I have some spare time (nice joke). Maybe the choice of transistors for the hardware-number-generator section is a little bit tricky. I remember actually having to choose the right ones in a bag of identically labelled BC237B. I should probably have tested their characteristics, but I don't have a curve tracer. Yes, a curve tracer is really somthing that I would like to get, someday. As for the group, I peek in from time to time, I am delighted and maybe also a little bit flattered, that the two Pentas are in the opening picture of this group, and I like the spirit of it, disinterested and friendly. In days like these it is not a small thing.
I wish a nice Holiday season to everybody
Keep (it) glowing
Giampaolo

Hello, Giampaolo, and thank you for showing up.

I love the design of the Penta, so I'm going forward and starting to build one. However, I've just realised that some of the most interesting words in Portuguese have 6 letters, so who knows an "Hexa" device might come to be sometime? Of course, I have no idea if it's possible to stick an extra digit/character there.

Anyway, I've got a few questions about the Penta.

- What modifications are needed for it to work under a 60Hz mains?
- What's that capacitor on pin 3 of the MC34063? It's not clear in your drawing, seems to be '1M'.
- There are 3 different drawings for capacitors, does that differ the electrolytic from ceramic, and so on?
- What's the dissipation on the resistors? don't know if there's any difference between the two different drawings of resistors also.
- What are the specifications (or just the type) of the four diodes making up a bridge at the main power source?

Thank you

(Everyone, please feel free to answer)

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

Hello, Giampaolo, and thank you for showing up.

I love the design of the Penta, so I'm going forward and starting to build one. However, I've just realised that some of the most interesting words in Portuguese have 6 letters, so who knows an "Hexa" device might come to be sometime? Of course, I have no idea if it's possible to stick an extra digit/character there.

Anyway, I've got a few questions about the Penta.

- What modifications are needed for it to work under a 60Hz mains?
- What's that capacitor on pin 3 of the MC34063? It's not clear in your drawing, seems to be '1M'.
- There are 3 different drawings for capacitors, does that differ the electrolytic from ceramic, and so on?
- What's the dissipation on the resistors? don't know if there's any difference between the two different drawings of resistors also.
- What are the specifications (or just the type) of the four diodes making up a bridge at the main power source?

Thank you

(Everyone, please feel free to answer)

Hello Marco,
Some answers to your questions:

The capacitor on pin 3 of the mC 34063 is 1 nF (1000 pf).
I have cleaned up a little bit the drawing. Only two types of capacitors: electrolitic or non-electrolitic.
Resistors are all the same: 1/4 W.
Diodes in the bridge are 1N4007
I have put the asm and hex files for the 60 Hz version in the web site(v 1.40C). The hardware is the same.

Making a Hexa out of the Penta would be a major task, not so much for the hardware but for the software. You'll have to rewrite it.
All the best
Giampaolo

--- In NEONIXIE-L@..., "giampaolo_minetti" <giampaolo.minetti@...> wrote:

Making a Hexa out of the Penta would be a major task, not so much for the hardware but for the software. You'll have to rewrite it.

Hello again, Giampaolo.
Decisions... decisions. I don't wanna miss on the fun of the Italian words, so I think I'll build a Penta in honor of my Italian roots AND a (an?) Hexa for Brazilian Portuguese words.

Can you explain a bit what I'd have to do in order to physically stick another 'digit' in that circuit, pending software?

Grazie

Marco

Hello,
googled eyed the computer and found many places for the 2000uf cap.
digikey
ebay, etc.

Of course shipping is the killer.

Michail

--- In NEONIXIE-L@..., "giampaolo_minetti" <giampaolo.minetti@...> wrote:

Hello,
I am the author of the Penta device.

Maybe the choice of transistors for the hardware-number-generator
section is a little bit tricky. I remember actually having to
choose the right ones in a bag of identically labelled BC237B.
I should probably have tested their characteristics, but I don't
have a curve tracer. Yes, a curve tracer is really somthing that I
would like to get, someday.

background:



Hello again, Giampaolo,

About these transistors, what differences among identically labeled transistors required you to chose one from another? I thought same parts acted all the same. And how do you test that portion of the circuit in order to determine whether it's working and you found the right ones?

Also, I can't find a 2000 uF capacitor (for the power source), so I suppose I can combine two 1000 uF capacitors in paralel there.

I have other questions, mostly about inputting the language data to the circuit once it's finished, but I ask that much later, once the thing is assembled (certainly, many months from now).

As usual, everyone, please feel free to pitch in.

Thanks

Marco

background:


Hello again, Giampaolo,

About these transistors ...

Also, I can't find a 2000 uF capacitor (for the power source),
so I suppose I can combine two 1000 uF capacitors in parallel
there. ...

Thanks

Marco

Nothing special about -> HOW <- the transistors are used on the MCU section. You can use just about any small signal NPN & PNP, where specified. Something like the 2N3904 (NPN) & 2N3906 (PNP) will do. You might squeeze out a couple of percentage points extra in efficiency, if you use a MPSA05 (NPN) & MPSA55 (PNP) to drive the IRF840 FET, on the power supply. But you'll get way more improvement by switching to a IRF740 (A or B) for the FET (IRF840 specified). Of course, use a good coil. One with a high saturation current.

As for the cap. They don't commonly make 2000uf any more. Use a 2200uf cap. The actual value isn't critical. The cap used might just have a +80/-20% tolerance anyways (1600uf-3600uf). Using two 1000uf caps, in parallel, is good too. Your combine ripple current limit is usually higher, than using a single cap. It this case its probably not a problem, but its something to keep in mind, for future apps.

I suspect that the parts in his schematic, were mostly the parts he had on hand, and he didn't refine his drawing for general manufacture. They haven't made 2000uf caps, as a standard value, for some time (decades). If they still sell them, they're going to charge a premium. You don't need anything special in that part of the circuit.

Capacitor and inductor values, for the most part, all have values with the following two significant digits:

10,15,22,33,47, & 68.

These are the most common (sometimes called 20% values). To a lesser degree you'll find these in between (10% values):

12,18,27,39,56, & 82.

So you will find capacitors made with values like 100uf, 3300uf, 470pf, etc. You won't find values like 2500pf or 500uf. If you do, they are from some 'old timers' junk bin, because such values where made at one time, but no longer.

On 10-08-03 09:42 AM, cagamba wrote:

About these transistors, what differences among identically labeled
transistors required you to chose one from another? I thought same
parts acted all the same. And how do you test that portion of the
circuit in order to determine whether it's working and you found the
right ones?

All thransistors of a given part will meet the published specs, but sometimes a circuit needs a Bit more gain (or a bit less) of is right at the breakdown voltage. sometimes folsk will select a part to avoid having to buy the higher spec part. (the same die selected into a better grade bin at factory testing, and given a different part number)

Years ago you could buy grab bags of "seconds" which did not meet any part number - or tested seconds which had a Paint dot to indicate what application in a radio they were for.



--
Charles MacDonald Stittsville Ontario
cmacd@... Just Beyond the Fringe

No Microsoft Products were used in sending this e-mail.

--- In NEONIXIE-L@..., Charles MacDonald <cmacd@...> wrote:

Years ago you could buy grab bags of [transistors] "seconds" which
did not meet any part number - or tested seconds which had a Paint
dot to indicate what application in a radio they were for.

You don't happen to have any documentation of what those "dots" mean, do you (if there was even any kind of standard)? I have a bunch of salvaged transistors whose only markings aside from EBC is either a colored dot, or the entire top of the TO-92 package is painted a particular color.

A.J.

On 10-08-05 12:18 AM, A.J. wrote:

--- In NEONIXIE-L@..., Charles MacDonald<cmacd@...> wrote:

Years ago you could buy grab bags of [transistors]... had a Paint
dot to indicate what application in a radio they were for.

You don't happen to have any documentation of what those "dots" mean, do you (if there was even any kind of standard)? I have a bunch of salvaged transistors whose only markings aside from EBC is either a colored dot, or the entire top of the TO-92 package is painted a particular color.

I have seen some data sheets where a part has a "grren" "yellow" "Blue" version on some parameter or other. I would not be surpised if some factory might not run all of a given run of a part through a sorting test and use a dot to indicate a test result and then mark a part number accordingly. this could be an OEM part number.

Compare a 2n3903 with a 2n3904 - probaly the 3903 is a 3904 that failed a test, but whould still fit a number of places in almost any product. Even a cent on a part is a big deal when you make 10,000 appliances.

Back in the tube days RCA used to screen tubes that way. Selecting say for low microphoonics or higher gain. sometimes the tubes were given a special number (the 1600 series) or just stamped with the customers name and shipped out - creating a mystery for TV repairmen who wonderd why a new tube did not fix a TV set (that had left the factory with a "selcted" "hot" RCA made tube.)

--
Charles MacDonald Stittsville Ontario
cmacd@... Just Beyond the Fringe

No Microsoft Products were used in sending this e-mail.