Vacuum Tube Calculator Schematic

[Terry Casey]

He is looking for a *digital* computer, and it does not have to be
complicated or work with a lot of digits.
So..under 100 tubes, obviously diode logic will be required.
.

Wikipedia states "The Colossus machines were ... the world's first
programmable, digital, electronic, computing devices. They used vacuum
tubes (thermionic valves) to perform the calculations."

Note the words *DIGITAL ... COMPUTING DEVICES* in there!

I visited Bletchley Park some years ago, and saw the Colossus project in
its early stages. They started by replicating one 19" rack and, IIRC,
were using vertical chassis modules perhaps 4U high. These used Octal
valves, remember, so we're not talking any kind of miniaturisation here!

Presumably they were able to test each module independently after they'd
built it and one module or two may suit the OP's needs. (I wasn't REALLY
suggesting he'd want to build the whole machine!)

The OP was particularly insistent on needing detailed schematics - and
these most definitely exist for Colossus!

Could be worth contacting the NMOC to suggest exactly what he has in
mind - or perhaps they might be able to suggest what sort of thing he
could do with an existing module of a combination of modules as a
stand-alone unit?

Terry

 

[Tim Shoppa]

The Obstinate Bitter  Donkey part of me ,  still disagrees with not
trying  something to speed things up.  If you want to strictly graph
performance you can look that up, and no reason to build anything.

If you put all the stray capacitances in a well-calibrated SPICE
model, you can come pretty close to real life.

The gotcha is that you have to know all the stray capacitances and
have a well-calibrated SPICE model.

 What Ifs are a valid point in your presentation, if you can prove
them , ie "If so and so had changed this component to this, and it
sped it up xx percent..."  It adds to your presentation.

The less evolved designs could be improved... but the more evolved
tube logic designs are very much tuned to the edge of practicality.
Look at the different speed grades of the HP AC-4 and how they have
tweaked each and every speedup capacitor in each flip-flop. The design
is actually quite a bit more evolved for manufacturability and
repeatability than many transistor designs.

Tim.

 

[Richard Henry]

schematics, please. and if neccesary, I have nixie tubes, however,
they would require a demux and only 3 bits (they aren't hex and I
ain't doin' BCD or converting to decimal).

Look, if someone can simply either tell me or give me a web page with
the schematics for:
a.) a half adder
b.) a full adder
and possibly c.) 1/2 of a 7474 equivalent (D-type flip-flop with
preset and clear)

I can do bare transistor logic. I just need to be able to do it with
tubes. A book on BN or Amazon would be fine. FYI, I THINK a 12Ax7
(where x is T, U, V, X or Y) makes a 2-input AND, OR, NAND or NOR gate

When I was in high school I constructed a half-adder out of hand-made
relays. I had paper plans to build a simple logic game device using
them, but soon realized I would not be able to afford all the
batteries needed to supply current to the relay coils.

 

[[email protected]]

Jeez, I go to sleep, wake up, go to school, come back, and there's a
bunch more messages.

Ok...
But most of them are useless.
Please stick to the topic. Useless messages are, to say the least,
useless. To say the most, cr*p.

 

[James Arthur]

Jeez, I go to sleep, wake up, go to school, come back, and there's a
bunch more messages.

Ok...
But most of them are useless.
Please stick to the topic. Useless messages are, to say the least,
useless. To say the most, cr*p.

You've gotten a number of good tips so far.

The thing you want doesn't seem to exist as such, so what do you
want at this point? I have some olde-tyme schematics of tube
logic circuits, if that's any help.

Oh, and you can make pretty much any logic circuit out of
neon bulbs, like the NE-2. Flip-flops, decade counters,
etc. NE-2's are cheap, need no heater, and it might be
fun to watch the calculator run (verrry slowwwly).


Do any of those sound useful to you?


James Arthur

 

[Jure Newsgroups]

Jeez, I go to sleep, wake up, go to school, come back, and there's a
bunch more messages.

Ok...
But most of them are useless.
Please stick to the topic. Useless messages are, to say the least,
useless. To say the most, cr*p.

if you have a chance , visit the Computer History museum,
where there are many wonderful things to see,
also, a great library.

http://www.computerhistory.org/


BTW, the Babbage difference engine is very interesting
http://www.computerhistory.org/babbage/

good luck,

Jure Z.

 

[[email protected]]

You've gotten a number of good tips so far.

The thing you want doesn't seem to exist as such, so what do you
want at this point?  I have some olde-tyme schematics of tube
logic circuits, if that's any help.

Oh, and you can make pretty much any logic circuit out of
neon bulbs, like the NE-2.  Flip-flops, decade counters,
etc.  NE-2's are cheap, need no heater, and it might be
fun to watch the calculator run (verrry slowwwly).

Do any of those sound useful to you?

James Arthur

I have a 5 pound bag of matched NE2s, would be glad to send some to
you via your science teacher.

Steve

 

[Rich Grise]

Does anyone know where I can find out how to design a calculator with
vacuum tubes, or where I can find an already-made schematic? It's for a
science fair.

Here are some gates and adders and memory drivers and stuff:
http://acms.synonet.com/bendix/tech/TechMan/tekrpt1.pdf

Have Fun! ;-)
Rich

 

[Rich Grise]

That might be too challenging for a vanity fair (sorry, science fair).
You would need around 5000 to 7000 tubes and 200 to 300 Amps to run it.
It might take up the entire fair ground as well. How much money do you
have?

Phaugh! You can build a 2-bit full adder with a handful of gates.
Admittedly, it might be the size of a coffee table, but that's just about
right for a science fair. Start with an "and" gate, an "or" gate, an
inverter, and look up logic diagrams for CPU stuff - mostly adders. ;-)

You'd use pushbuttons or toggle switches for the inputs, and NE-2s for
the outputs. ;-)

Cheers!
Rich

 

[Rich Grise]

Any more help would be appreciated. Does anyone know where I can find a
book on digital logic using vacuum tubes, or possibly general vacuum tube
theory? It needs to have schematics.

You might have to use two books in concert - one about logic stuff, and
another on how to put tubes into the circuits.

BTW, this is for next year's science fair, right? ;-P

Have Fun!
Rich

 

[Rich Grise]

Multiplication and Division need hundreds to thousands transistors/ tubes.

You could do it with a couple of dozen, if you have serial memory and know
how to do it serially. You only have to do one bit at a time if you do it
serially. It might take a moment or three, but the job will eventually get
done. ;-)

Serial memory: think of a 64-track tape in a loop, with pairs of read/
erase/write heads... Kind of a magnetic Turing machine on steroids. ;-)

Cheers!
Rich

 

[Rich Grise]

Look, if someone can simply either tell me or give me a web page with the
schematics for:
a.) a half adder
http://www.google.com/search?q=half+adder+schematic

b.) a full adder
http://www.google.com/search?q=full+adder+schematic

and possibly c.) 1/2 of a 7474 equivalent (D-type flip-flop with preset
and clear)
http://www.google.com/search?q=d+flip+flop+schematic

I can do bare transistor logic. I just need to be able to do it with
tubes.

Just put tubes in place of transistors, and adjust the impedances and
biasing appropriately. ;-)

Have Fun!
Rich

 

[Rich Grise]

maybe I should clarify more.I need a true schematic, showing how to get
plate voltage, how to get heater voltage, and showing all resistor,
capacitors and basically every single discrete component.

This help?

The purpose of a science fair is to showcase the student's work. So if I
hand you all this stuff on a silver platter, then that entitles me to any
and all prizes or other accolades, including my transportation to and from
the awards ceremony and any necessary lodging, transportation, and
$120.00/day per diem, so you can show everyone who really did it for you,
right?

Good Luck.
Rich

 

[Rich Grise]

Jeez, I go to sleep, wake up, go to school, come back, and there's a bunch
more messages.

Ok...
But most of them are useless.
Please stick to the topic. Useless messages are, to say the least,
useless. To say the most, cr*p.

So are useless googlies asking for people to do their homework for them,
for free, no less!

Don't start vast projects with a half-vast ideas.

Good Luck!
Rich

 

[JosephKK]

That doesn't seem to have any schematics...
and linnix (like the name, use linux all the time): I really don't
think so. To clarify: I have built a "calculator" from CMOS SSI. It is
a 6-bit adder. I am building an 8-bit "calculator" from TTL logic,
also SSI (with 2 74181's). It's got 32 functions, of which about 4 are
real and essential math. The others are mostly logic.
I also want to do it only in binary, as my other calculators have
been.

Any more help would be appreciated. Does anyone know where I can find
a book on digital logic using vacuum tubes, or possibly general vacuum
tube theory? It needs to have schematics.

Why this Jones for schematics? Are you completely ignorant of
electronic principles?

 

[JosephKK]

They are just simple adding machines.


Multiplication and Division need hundreds to thousands transistors/
tubes.

No, they don't. Design of combined sequential and combinatorial
circuits is all that is needed. I could maybe do it in less than 100
tubes / transistors. Part of the problem is partitioning the
complexity between the sequential part and the combinatorial part.

 

[JosephKK]

Eh? Eh?
All required logic is the one bit adder with carry, plus a pair of shift
registers. With the associated control and I/O, it takes 200...300 valves.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

Gee, are you talking about 64 bit words? In the general case one tube
per flipflop or gate. 1/2 tube for an inverter.

 

[JosephKK]

The HP9100 programmable calculator used about 20 SIP-potted
discrete-transistor flipflops in its core and a lot of ROM of various
types. Program and data storage was magnetic cores, and the display
was 7-segment, vector characters on a CRT.

I should think that a "microcoded" (simple state machine with big
diode ROM) calculator could be done with about 20 or 30 dual triodes
and some sort of storage mechanism, capacitors maybe. But it would be
a heap of work.

John

A direct state machine yes; a microcoded one no.

 

[JosephKK]

Are they too high, or too low?

Too sparky. (The low spark of high-heeled boys)

 

[JosephKK]

Or build a Colossus clone. While the real colossus filled a room, a
single function subset might be interesting. colossus was a WWII
secret code cracking processor. There is a question if it was truly
a computer, but it had one thing you might find interesting, the data
input was a paper tape with holes in it. Could you make a vacuum adder
using two paper tapes and a readout? That might be easier to find
then a strowger switch or dekatons. I like the strowger switch ,
phone dial driven system.

Steve.

Finally had to look it up. Up the universe, the US Navy destroyer i
was on the mid 1970's had an internal telephone system (200 lines 20
connections i think) based on descendants of the Strowger switch. Yes
i am certain, i saw it in operation. Now that is technical longevity.