3 Mar
2013
3 Mar
'13
2:17 p.m.
James (and Chris),
I graduated in 1980, McCallum High School, Austin, Texas. We
had a slide rule team, with a coach. In addition, my Biology and
physics teachers all let me use slide rule for all homework and
tests, giving me credit if my answer was within about 0.5% or so.
Dunno whether that counts, but if so would push the date out to 1980.
I did get a TI-59 (still have it, sticky keyboard and I'll
bet the card reader doesn't work) middle of my senior year. That was
a pleasant culture shock...
I don't know that I ever saw one of the six-foot-long
"supercomputers" :-) .
At 20:07 -0600 3/2/13, <James> wrote:
This leads me to my belief that I was the last slide
rule teacher.?
In 1975, in Ghana, ....
--
- Mark 210-379-4635
-----------------------------------------------------------------------
Large Asteroids headed toward planets
inhabited by beings that don't have
technology adequate to stop them:
Think of it as Evolution in Fast-Forward.
3 Mar
3 Mar
2:41 p.m.
New subject: Slide Rules
I graduated from high school in 1987. Nobody had ever heard of a
slide rule by that time. They seem to have faded very quickly.
-Dave
On 03/03/2013 02:17 PM, Mark Tapley wrote:
James (and Chris),
I graduated in 1980, McCallum High School, Austin, Texas. We had a
slide rule team, with a coach. In addition, my Biology and physics
teachers all let me use slide rule for all homework and tests, giving me
credit if my answer was within about 0.5% or so. Dunno whether that
counts, but if so would push the date out to 1980.
I did get a TI-59 (still have it, sticky keyboard and I'll bet the
card reader doesn't work) middle of my senior year. That was a pleasant
culture shock...
I don't know that I ever saw one of the six-foot-long
"supercomputers" :-) .
At 20:07 -0600 3/2/13, <James> wrote:
--
Dave McGuire, AK4HZ
New Kensington, PA
This leads me to my belief that I was the last
slide rule teacher.? In
1975, in Ghana, ....
3:25 p.m.
New subject: Slide Rules
On 03/03/2013 11:41 AM, Dave McGuire wrote:
I graduated from high school in 1987. Nobody had ever heard of a
slide rule by that time. They seem to have faded very quickly.
Probably like iPads today, slide rules in college were often a target of
thieves. That's how I lost my big Pickett aluminum rule, and then later
a Post Versalog. Someone just snatched them when my attention was
distracted.
Some things never change...
--Chuck
4 Mar
4 Mar
7:36 p.m.
New subject: Slide Rules
On 3 March 2013 19:41, Dave McGuire <mcguire at neurotica.com> wrote:
I graduated from high school in 1987. Nobody had ever heard of a
slide rule by that time. They seem to have faded very quickly.
'85 here. Never ever saw one in any educational/scientific context.
Knew a few older scientists & engineers who kept one around for
sentimental value.
My father was one. He never taught me to use them, though.
Like the currency pounds, shillings and pence, or the units of ounces,
pounds, hundredweights, furlongs, leagues, degrees Fahrenheit and so
on, they were all gone before my time. I entered school in about 1971.
To this day, I have no clue how many "oz" in a "lb" or "lb"
in a
stone, or yards in a mile, or any of that stuff. All alien to me:
weird, incomprehensible, confusing and a little scary.
I am waiting for several late-40s or older types to tell me that there
are in fact 235 oz/lb and 12357.3 lb/st and 6.2343648?10?? yards to
the mile and that it all makes /perfect/ sense if you just remember
these and 460924707 simple, obvious numbers.
That obviously, although Fahrenheit is a simple clear logical scale
that defines 0? as the temperature of the earlobe of a Siberian pine
marten that has been inserted into a 42 ton snowdrift for exactly
3.461376 hours in Perm on the 15 Feb 1765 and 100? is a slight
mismeasurement of the average rectal temperature of an unladen African
swallow at cruising speed, it makes perfect sense because you see 88?
is a nice day and 46? is a howling blizzard and these are sensible
human numbers. I mean, who would want a scale from 0 for freezing to
100 for boiling? That's just crazy talk!
--
Liam Proven ? Profile: http://lproven.livejournal.com/profile
Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven
MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven
Tel: +44 20-8685-0498 ? Cell: +44 7939-087884
5 Mar
5 Mar
5:30 p.m.
New subject: Slide Rules
On 3 March 2013 19:41, Dave McGuire <mcguire at neurotica.com> wrote:
1984 here. Never used a slide rule in anger at school, although I did
know how to use one. My father showed me the basics and I figured out
some other tricks.
I graduated from high school in 1987. Nobody had ever heard of a
slide rule by that time. They seem to have faded very quickly.
'85 here. Never ever saw one in any educational/scientific context.
Knew a few older scientists & engineers who kept one around for
sentimental value. Like the currency pounds, shillings and pence, or the
units of ounces,
pounds, hundredweights, furlongs, leagues, degrees Fahrenheit and so
on, they were all gone before my time. I entered school in about 1971.
I do find I ahve to be able to work in imperial units. American computer
equipment is full of imperial-sized UNC screws, IC pins are on a 0.1"
pitch (2.5mm is not close enough), and so on.
To this day, I have no clue how many "oz" in
a "lb" or "lb" in a
16 and 14 respectively.
stone, or yards in a mile, or any of that stuff. All
alien to me:
1760, a number whcih I can easily remeebr from anotehr context [1]
[1] And yes it is related to classic computers. What is it?
weird, incomprehensible, confusing and a little scary.
Actually, for practicla purposes 10 is a very inconvenient base for a
measuremtn sytem becuase it has so few factors.
And the conversion of in to cm (2.54cm in an inch) is plain painful. 2.55
or 2.56 would make my life a lot easier.
human numbers. I mean, who would want a scale from 0
for freezing to
100 for boiling? That's just crazy talk!
Not me!. Assuming you mean pure water at normal atmospheric pressure I'll
ahve 273.15 for freezign and 373.15 for boiling.
-tony
6:49 p.m.
New subject: Slide Rules
On 03/05/2013 02:30 PM, Tony Duell wrote:
1984 here. Never used a slide rule in anger at school,
although I did
know how to use one. My father showed me the basics and I figured out
some other tricks.
I'm sure that a few geezers remember the 6 ft. long giant slide rules
hanging just above the blackboard used to teach the use of the thing.
I recall a "spiral" slide rule in a round cylindrical package also.
Done to extend the length of the scale but not the physical length of
the rule.
And then there were the circular slide rules. Never used one.
--Chuck
P.S. I'm sure that we're close to the "chalk, blackboard? What are you
talking about?" era...
7:05 p.m.
New subject: Slide Rules
On 3/5/2013 3:49 PM, Chuck Guzis wrote:
I'm sure that a few geezers remember the 6 ft. long giant slide rules
hanging just above the blackboard used to teach the use of the thing.
have one available. Post, I think
I recall a "spiral" slide rule in a round
cylindrical package also.
Done to extend the length of the scale but not the physical length of
the rule.
And then there were the circular slide rules. Never used one
I have always used a
circular. The first time I used a 4 or 5" in
school, I decided I needed a better rule, and found an 8" one for sale.
It was enamel on aluminum and very durable. The main reason was just
additional precision.
I looked for some info online as it has been too long to remember what
the scale equivalent was on mine, but wikipedia says a 10" had 31cm of
equivalent length. The main thing people didn't like that I recalled
was the dual cursor you had for using the circular ones like that. They
have no moving scales other than the two cursors, and you would set the
two cursors to get the same action as you got by sliding the main slide
on a normal straight rule. It could be fun if you didn't do it right
and nudged the scale when using it.
thanks
Jim
7:29 p.m.
New subject: Slide Rules
On Tue, 5 Mar 2013, Jim Stephens wrote:
I looked for some info online as it has been too long
to remember what
the scale equivalent was on mine, but wikipedia says a 10" had 31cm of
equivalent length.
You do NOT need nor want Wikipedia for that!
Not good to become dependent :-)
Circumference is PI times diameter.
about 80cm
31 INCHES would be close. But, common problem with slide rules is
not getting the decimal point or units correct. :-)
31 inches would be closer to correct than 31.4159, since the diameter
of the scale would be less than the outer diameter of the rule in most cases.
I had a circular rule that consisted of two disks on a common spindle. It
would have been nice it were better made.
--
Grumpy Ol' Fred cisin at xenosoft.com
11:35 p.m.
New subject: Slide Rules
On 3/5/2013 4:29 PM, Fred Cisin wrote:
You do NOT need nor want Wikipedia for that!
Not good to become dependent:-)
Circumference is PI times diameter.
I should have checked the math. it isn't
pi circumference. It is a
spiral, not a circular scale. I didn't want to try to guess, or
calculate it because I didn't recall how many times it wrapped.
3 * 8 inches isn't the right number either.
Jim
6 Mar
6 Mar
1:16 p.m.
New subject: Slide Rules
> You do NOT need nor want Wikipedia for that!
> Not good to become dependent:-)
> Circumference is PI times diameter.
On Tue, 5 Mar 2013, Jim Stephens wrote:
I should have checked the math. it isn't pi
circumference. It is a
spiral, not a circular scale. I didn't want to try to guess, or
calculate it because I didn't recall how many times it wrapped.
3 * 8 inches isn't the right number either.
Ah! Sorry
I thought that we were still talking about circular.
Flat spiral? (like a [non-computer] "record" (ancient predecessor of
MP3), or like an SA400 stepper cam))
or helix? (like a "wax cylinder" (predecessor of "record") or lead
screw
(such as a Micropolis stepper))
If flat spiral, we can estimate the length by PI times the
arithmetic mean of the diameter (add the innermost, outermost,
and appropriate intermediates and divide by number of turns)
If helix, we can estimate the length by the hypoteneuse of
a right triangle (consisting of the small distance along
the cylinder of the start and end, and the [multiple]
circumference (diameter of the cylinder times number
of turns times PI)) It won't be MUCH different from
just the circumference times nuber of turns.
For the squares and square roots needed for calculating the
hypoteneuse, use the A and D scales (or B and C) of the slide rule.
If the C and D scales do not have a mark for PI, add one.
--
Grumpy Ol' Fred cisin at xenosoft.com
3:19 p.m.
New subject: Slide Rules
On Wed, 6 Mar 2013, Fred Cisin wrote:
If flat spiral, we can estimate the length by PI times
the
arithmetic mean of the diameter (add the innermost, outermost,
and appropriate intermediates and divide by number of turns)
ERROR! (in my logorrheic babbling)
That should be PI times the arithmetic mean of the diameter times the
number of turns.
(PI * number of turns times ((innermost+outermost diameters)/2))
(or PI * number of turns times (innermost RADIUS + outermost RADIUS))
Would attempting to look up the answer in Wikipedia increase or
decrease the number of errors? Would it strengthen the strange
belief that "doing the math" is "TOO HARD"?
Optional Edison method: wrap a string following the scale and then
measure the string. (Apple's ad saying that "Edison could have
simulated, instead of trying different filaments", was antithetical
to the man's philosophy and style)
7 Mar
7 Mar
1:06 a.m.
New subject: Slide Rules
I use this method to determine the lengthof a clock spring in a barrel. One can even
estimatethe part that is unwound at the center as the coils areclose to evenly spaced. Two
calculation and I knowthe length.Dwight
Date: Wed, 6 Mar 2013 12:19:08 -0800
From: cisin at xenosoft.com
To: cctalk at classiccmp.org
Subject: Re: Slide Rules
On Wed, 6 Mar 2013, Fred Cisin wrote:
If flat spiral, we can estimate the length by PI
times the
arithmetic mean of the diameter (add the innermost, outermost,
and appropriate intermediates and divide by number of turns)
ERROR! (in my logorrheic babbling)
That should be PI times the arithmetic mean of the diameter times the
number of turns.
(PI * number of turns times ((innermost+outermost diameters)/2))
(or PI * number of turns times (innermost RADIUS + outermost RADIUS))
Would attempting to look up the answer in Wikipedia increase or
decrease the number of errors? Would it strengthen the strange
belief that "doing the math" is "TOO HARD"?
Optional Edison method: wrap a string following the scale and then
measure the string. (Apple's ad saying that "Edison could have
simulated, instead of trying different filaments", was antithetical
to the man's philosophy and style)
12:25 p.m.
New subject: Slide Rules
Wikipedia might have a photo of a rule similar to mine along with a
verifiable explanation of what the length of that spiral scale is. I
didn't and my rule was buried. I already said I brain farted an quoted
a bad stat. I was not going to do wikipedia w/o verification or because
the math is too hard. I did it because I have no idea how many times
the scale went round, and didn't want to guess. Is guessing and babble
better than wikipedia even if the math is right?
On 3/6/2013 12:19 PM, Fred Cisin wrote:
Would attempting to look up the answer in Wikipedia
increase or
decrease the number of errors? Would it strengthen the strange
belief that "doing the math" is "TOO HARD"?
12:43 p.m.
New subject: Slide Rules
On Thu, 7 Mar 2013, Jim Stephens wrote:
Wikipedia might have a photo of a rule similar to mine
along with a
verifiable explanation of what the length of that spiral scale is. I
didn't and my rule was buried. I already said I brain farted an quoted
a bad stat.
'sOK It happens
I was not going to do wikipedia w/o verification or
because
the math is too hard. I did it because I have no idea how many times
the scale went round, and didn't want to guess. Is guessing and babble
better than wikipedia even if the math is right?
maybe :-) certainly more fun
So, is it a flat spiral or a helix?
Either one at 10" diameter is an impressively long scale, for a LOT of
accuracy!
1:23 p.m.
New subject: Slide Rules
On 3/7/2013 9:59 AM, Dennis Boone wrote:
That was why I had both a 4" and the monster. The jump up in accuracy w
both expensive and large to the detriment of being able to have it with
me as I schelped from class to class. I didn't want to damage the
legend on the large one, and it was already huge in itself. And there
was only a lambskin leather cover for it which wouldn't do with everyday
carrying. It could have used a hard case, but then would have become
like the old "luggable" systems of pre laptop days. You could have
carried it, but would not want to. And I don't mean as large as the
luggable, just the choice was not real, you would not want one in your
sack of stuff in a hard case.
Fred, you stretched my head when you said helix vs. spiral. do you get
a helix on a flat plane with just lines on it? I thought helix would be
cylinder ruled with a line. maybe I'm taking what you meant out of
context and you were referring back to the cylindrical devices. I would
think the helix would be quite a bit harder to navigate than the
spiral. at least on the spiral, you could always see the entire
picture, whereas with the helix / cylinder you'd end up with only
viewing a stack of legends on a side, part of the helix at any one given
time. knowing which vertical one to pick on which cursor could get to
be fun.
thanks
Jim
Either one at
10" diameter is an impressively long scale, for a LOT of
accuracy!
The accuracy builds up surprisingly slowly as the scale lengthens.
De
8 Mar
8 Mar
4:24 p.m.
New subject: Slide Rules
Fred, you stretched my head when you said helix vs.
spiral. do you get
a helix on a flat plane with just lines on it? I thought helix would be
cylinder ruled with a line. maybe I'm taking what you meant out of
It is.
Helical slide rules, like the Otis King are cuylindrical with the scale
forming a helix around the cylcider (like a screw thread). In the cae of
the Otis King there are 2 cylders with scales that sldie one within the
other and also rotate relative to each other and a cydindrical cursor
that sldis and rotatesa over the outside with an indicaotr lien at eack end.
To do multiplication, you set the line on the cursor agains the '1' on
the lower scale and sldie//rotate the upper scale to align the line at
that end of the cursor agaisn the first number on that scale. Then,
keeping the 2 scales fixed realtive to each other, you move the cursor so
that the bottom line is against the second number on the lower scale. The
upper line then indicates the product o nthe upper scale.
-tony
6:03 p.m.
New subject: Slide Rules
On 03/08/2013 01:24 PM, Tony Duell wrote:
It was my original statement that referred to "spiral" when I meant helix.
On the other hand if you take the definition:
"A three-dimensional curve that turns around an axis at a varying
distance while moving parallel to the axis." with the variation of the
distance being infinitely small, you have a helix. In other words, a
helix is simply a degenerate case of a three-dimensional spiral.
But I did mean "helix".
--Chuck
Fred, you
stretched my head when you said helix vs. spiral. do you get
a helix on a flat plane with just lines on it? I thought helix would be
cylinder ruled with a line. maybe I'm taking what you meant out of
It is.
Helical slide rules, like the Otis King are cuylindrical with the scale
forming a helix around the cylcider (like a screw thread). In the cae of
the Otis King there are 2 cylders with scales that sldie one within the
other and also rotate relative to each other and a cydindrical cursor
that sldis and rotatesa over the outside with an indicaotr lien at eack end.
6:53 p.m.
New subject: Slide Rules
On Fri, 8 Mar 2013, Chuck Guzis wrote:
It was my original statement that referred to
"spiral" when I meant helix.
On the other hand if you take the definition:
"A three-dimensional curve that turns around an axis at a varying
distance while moving parallel to the axis." with the variation of the
distance being infinitely small, you have a helix. In other words, a
helix is simply a degenerate case of a three-dimensional spiral.
But I did mean "helix".
Nothing wrong with that. But that's why we needed clarification
and disambiguation for visualization. That was why I asked whether
it was like the stepper of an SA400 or like a Micropolis 5.25.
Making one scale out of a transparent material opens up lots of
possibilities.
Or, the scale could be mechanically linked to a potentiometer,
followed by either A/D or analog computation.
Whoever comes up with the stupidest idea should patent it,
since that's here the money will probably be.
--
Grumpy Ol' Fred cisin at xenosoft.com
11:09 p.m.
New subject: Slide Rules
On 03/08/2013 03:53 PM, Fred Cisin wrote:
Or, the scale could be mechanically linked to a
potentiometer,
followed by either A/D or analog computation.
Nothing stupid about analog computers. Whatever happened to "hybrid
computing"? I remember seeing a big demo at Argonne, but it sort of
slipped away from notice.
I've mentioned Curta calculators eariler (a (wealthy) classmate had one
and it was a real hoot to play with), but I also recall a project
published in Radio-Electronics(?) that used neon lamps and a couple of
vacuum tubes (12AU7 type?) with a rotary telephone dial for input.
Anyone ever build that one?
--Chuck
11:30 p.m.
New subject: Slide Rules
On Friday, March 08, 2013 08:09:45 PM Chuck Guzis wrote:
I've mentioned Curta calculators eariler (a
(wealthy) classmate had one
and it was a real hoot to play with), but I also recall a project
published in Radio-Electronics(?) that used neon lamps and a couple of
vacuum tubes (12AU7 type?) with a rotary telephone dial for input.
Anyone ever build that one?
--Chuck
I haven't built (though I've got all the stuff here to do so), but here's the
article.
http://www.nzeldes.com/HOC/images/PE_1967_DialComputer.pdf
Alexis.
9 Mar
9 Mar
2:09 a.m.
New subject: Slide Rules
On 03/08/2013 08:30 PM, Alexis Kotlowy wrote:
I haven't built (though I've got all the stuff
here to do so), but here's the
article.
http://www.nzeldes.com/HOC/images/PE_1967_DialComputer.pdf
That's the one, all right. Thanks!
There was also a project at around the same time that involved making
your own Morse-code keyboard. It used commodity switches to create a
three-tier keyboard and I think didn't use much more than relays and
diodes to do the job.
Anyone remember that one? Those just happen to stick in my mind from
that time. Of course now it would just be a sub $1 MCU with a PC
keyboard, but along with those tic-tac-toe machines that used stepping
relays the projects were pretty memorable as an example of what could be
done with early experimenter digital electronics.
--Chuck
8 Mar
8 Mar
11:45 p.m.
New subject: Slide Rules
On 2013 Mar 8, at 3:53 PM, Fred Cisin wrote:
..
Making one scale out of a transparent material opens up lots of
possibilities.
Or, the scale could be mechanically linked to a potentiometer,
followed by either A/D or analog computation.
There was this from the 60s, basically an 'electric slide rule':
http://www.futurebots.com/cpu.htm
look for:
"Analog Computer Science Fair Computer Kit 1960's, I got one, WOW."
I like how the box says "As accurate as a slide-rule".
Presumably it uses standard log pots, aka volume controls.
Somebody describes it here:
http://tech.groups.yahoo.com/group/friendsofdigicomp/message/141
Whoever comes up with the stupidest idea should patent
it,
since that's here the money will probably be.
9 Mar
9 Mar
3:56 p.m.
New subject: Slide Rules
That's what I was expecting, but looking at the dial (as much as one
can see in the photos), they appear to be linear, so I figured it was
taking advantage of log pots (or is there a log/anti-log problem
there anyways?). Considering it more, a typical log pot may not give
an accurate enough log function to be very good for the task, so
you're probably right. Maybe there's another principle involved.
Another web site refers to a popular electronics article with a
similar design (I think I've seen the article in the past) but
doesn't say which issue.
On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
Actually it makes more sense to use alinear one with
log scales on
the dial.Dwight
> From: hilpert at cs.ubc.ca
> ---snip---
>
> I like how the box says "As accurate as a slide-rule".
>
> Presumably it uses standard log pots, aka volume controls.
10 Mar
10 Mar
10:36 a.m.
New subject: Slide Rules
Actually, after giving it a little thought, it would use linearpots and scales. It would
be voltage dividers and a balancingmeter.Remeber, a pot forms a ratio across a
resistor.Dwight
From: hilpert at cs.ubc.ca
That's what I was expecting, but looking at the dial (as much as one
can see in the photos), they appear to be linear, so I figured it was
taking advantage of log pots (or is there a log/anti-log problem
there anyways?). Considering it more, a typical log pot may not give
an accurate enough log function to be very good for the task, so
you're probably right. Maybe there's another principle involved.
Another web site refers to a popular electronics article with a
similar design (I think I've seen the article in the past) but
doesn't say which issue.
On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
Actually it makes more sense to use alinear one
with log scales on
the dial.Dwight
> From: hilpert at cs.ubc.ca
> ---snip---
>
> I like how the box says "As accurate as a slide-rule".
>
> Presumably it uses standard log pots, aka volume controls.
2:50 p.m.
New subject: Slide Rules
I did some searching on the web but I was surprisedthat no one has posted a schematic for
it.Dwight
Actually, after giving it a little thought, it would
use linearpots and scales. It would be voltage dividers and a balancingmeter.Remeber, a
pot forms a ratio across a resistor.Dwight
From: hilpert at cs.ubc.ca
That's what I was expecting, but looking at the dial (as much as one
can see in the photos), they appear to be linear, so I figured it was
taking advantage of log pots (or is there a log/anti-log problem
there anyways?). Considering it more, a typical log pot may not give
an accurate enough log function to be very good for the task, so
you're probably right. Maybe there's another principle involved.
Another web site refers to a popular electronics article with a
similar design (I think I've seen the article in the past) but
doesn't say which issue.
On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
Actually it makes more sense to use alinear one
with log scales on
the dial.Dwight
> From: hilpert at cs.ubc.ca
> ---snip---
>
> I like how the box says "As accurate as a slide-rule".
>
> Presumably it uses standard log pots, aka volume controls.
3:22 p.m.
New subject: Slide Rules
Well, I assumed it was doing a simple V R ratio / sum-of-logs of two
of the controls with a null-point balance with the third, however one
of the sites on the web showed a bag of caps and transistors involved
in the construction so perhaps it's using some AC principle, or that
may be a mislead.
I'm going to try to find the PE article in the library at the radio
museum this afternoon.
On 2013 Mar 10, at 11:50 AM, dwight elvey wrote:
I did some searching on the web but I was
surprisedthat no one has
posted a schematic for it.Dwight
> Actually, after giving it a little thought, it would use
> linearpots and scales. It would be voltage dividers and a
> balancingmeter.Remeber, a pot forms a ratio across a resistor.Dwight
>> From: hilpert at cs.ubc.ca
>
>>
>> That's what I was expecting, but looking at the dial (as much as one
>> can see in the photos), they appear to be linear, so I figured it
>> was
>> taking advantage of log pots (or is there a log/anti-log problem
>> there anyways?). Considering it more, a typical log pot may not give
>> an accurate enough log function to be very good for the task, so
>> you're probably right. Maybe there's another principle involved.
>>
>> Another web site refers to a popular electronics article with a
>> similar design (I think I've seen the article in the past) but
>> doesn't say which issue.
>>
>>
>> On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
>>> Actually it makes more sense to use alinear one with log scales on
>>> the dial.Dwight
>>>> From: hilpert at cs.ubc.ca
>>>> ---snip---
>>>>
>>>> I like how the box says "As accurate as a slide-rule".
>>>>
>>>> Presumably it uses standard log pots, aka volume controls.
>>
11 Mar
11 Mar
12:58 a.m.
New subject: Slide Rules
It seems like I recall two types. There was the one withthe linear scale ( radio shack )
and another with log scales.Dwight
From: hilpert at cs.ubc.ca
Well, I assumed it was doing a simple V R ratio / sum-of-logs of two
of the controls with a null-point balance with the third, however one
of the sites on the web showed a bag of caps and transistors involved
in the construction so perhaps it's using some AC principle, or that
may be a mislead.
I'm going to try to find the PE article in the library at the radio
museum this afternoon.
On 2013 Mar 10, at 11:50 AM, dwight elvey wrote:
> I did some searching on the web but I was surprisedthat no one has
> posted a schematic for it.Dwight
>
>> Actually, after giving it a little thought, it would use
>> linearpots and scales. It would be voltage dividers and a
>> balancingmeter.Remeber, a pot forms a ratio across a resistor.Dwight
>>> From: hilpert at cs.ubc.ca
>>
>>>
>>> That's what I was expecting, but looking at the dial (as much as one
>>> can see in the photos), they appear to be linear, so I figured it
>>> was
>>> taking advantage of log pots (or is there a log/anti-log problem
>>> there anyways?). Considering it more, a typical log pot may not give
>>> an accurate enough log function to be very good for the task, so
>>> you're probably right. Maybe there's another principle involved.
>>>
>>> Another web site refers to a popular electronics article with a
>>> similar design (I think I've seen the article in the past) but
>>> doesn't say which issue.
>>>
>>>
>>> On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
>>>> Actually it makes more sense to use alinear one with log scales on
>>>> the dial.Dwight
>>>>> From: hilpert at cs.ubc.ca
>>>>> ---snip---
>>>>>
>>>>> I like how the box says "As accurate as a slide-rule".
>>>>>
>>>>> Presumably it uses standard log pots, aka volume controls.
>>>
1:33 a.m.
New subject: Slide Rules
The Popular Electronics article is December 1961. I think it is as
you are suggesting, two cascaded pots, both wired as voltage
dividers, so you get two ratios and hence mulitplication: Vout = Vin*
(R1p/R1t)*(R2p/R2t) where p & t are the position and total Rs, Vout
is then null balanced against the third pot. The 2nd pot R is much
larger than the 1st to minimise loading error on the 1st.
Apparently some versions used a meter and DC, and some used an audio
oscillator and AC, with headphones replacing the null meter, which
explains the caps and transistors I saw.
No logs and even simpler than I thought.
On 2013 Mar 10, at 9:58 PM, dwight elvey wrote:
It seems like I recall two types. There was the one
withthe linear
scale ( radio shack ) and another with log scales.Dwight
From: hilpert at cs.ubc.ca
>
> Well, I assumed it was doing a simple V R ratio / sum-of-logs of two
> of the controls with a null-point balance with the third, however one
> of the sites on the web showed a bag of caps and transistors involved
> in the construction so perhaps it's using some AC principle, or that
> may be a mislead.
>
> I'm going to try to find the PE article in the library at the radio
> museum this afternoon.
>
>
> On 2013 Mar 10, at 11:50 AM, dwight elvey wrote:
>
>> I did some searching on the web but I was surprisedthat no one has
>> posted a schematic for it.Dwight
>>
>>> Actually, after giving it a little thought, it would use
>>> linearpots and scales. It would be voltage dividers and a
>>> balancingmeter.Remeber, a pot forms a ratio across a
>>> resistor.Dwight
>>> From: hilpert at cs.ubc.ca
>>>
>>>>
>>>> That's what I was expecting, but looking at the dial (as much
>>>> as one
>>>> can see in the photos), they appear to be linear, so I figured it
>>>> was
>>>> taking advantage of log pots (or is there a log/anti-log problem
>>>> there anyways?). Considering it more, a typical log pot may not
>>>> give
>>>> an accurate enough log function to be very good for the task, so
>>>> you're probably right. Maybe there's another principle involved.
>>>>
>>>> Another web site refers to a popular electronics article with a
>>>> similar design (I think I've seen the article in the past) but
>>>> doesn't say which issue.
>>>>
>>>>
>>>> On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
>>>>> Actually it makes more sense to use alinear one with log
>>>>> scales on
>>>>> the dial.Dwight
>>>>> From: hilpert at cs.ubc.ca
>>>>>> ---snip---
>>>>>>
>>>>>> I like how the box says "As accurate as a slide-rule".
>>>>>>
>>>>>> Presumably it uses standard log pots, aka volume controls.
10:44 a.m.
New subject: Slide Rules
I think the RS one used some of the transistors as a buffer to isolatethe pots as
well.Dwight > From: hilpert at cs.ubc.ca
The Popular Electronics article is December 1961. I think it is as
you are suggesting, two cascaded pots, both wired as voltage
dividers, so you get two ratios and hence mulitplication: Vout = Vin*
(R1p/R1t)*(R2p/R2t) where p & t are the position and total Rs, Vout
is then null balanced against the third pot. The 2nd pot R is much
larger than the 1st to minimise loading error on the 1st.
Apparently some versions used a meter and DC, and some used an audio
oscillator and AC, with headphones replacing the null meter, which
explains the caps and transistors I saw.
No logs and even simpler than I thought.
On 2013 Mar 10, at 9:58 PM, dwight elvey wrote:
It seems like I recall two types. There was the
one withthe linear
scale ( radio shack ) and another with log scales.Dwight
From: hilpert at cs.ubc.ca
>
> Well, I assumed it was doing a simple V R ratio / sum-of-logs of two
> of the controls with a null-point balance with the third, however one
> of the sites on the web showed a bag of caps and transistors involved
> in the construction so perhaps it's using some AC principle, or that
> may be a mislead.
>
> I'm going to try to find the PE article in the library at the radio
> museum this afternoon.
>
>
> On 2013 Mar 10, at 11:50 AM, dwight elvey wrote:
>
>> I did some searching on the web but I was surprisedthat no one has
>> posted a schematic for it.Dwight
>>
>>> Actually, after giving it a little thought, it would use
>>> linearpots and scales. It would be voltage dividers and a
>>> balancingmeter.Remeber, a pot forms a ratio across a
>>> resistor.Dwight
>>> From: hilpert at cs.ubc.ca
>>>
>>>>
>>>> That's what I was expecting, but looking at the dial (as much
>>>> as one
>>>> can see in the photos), they appear to be linear, so I figured it
>>>> was
>>>> taking advantage of log pots (or is there a log/anti-log problem
>>>> there anyways?). Considering it more, a typical log pot may not
>>>> give
>>>> an accurate enough log function to be very good for the task, so
>>>> you're probably right. Maybe there's another principle involved.
>>>>
>>>> Another web site refers to a popular electronics article with a
>>>> similar design (I think I've seen the article in the past) but
>>>> doesn't say which issue.
>>>>
>>>>
>>>> On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
>>>>> Actually it makes more sense to use alinear one with log
>>>>> scales on
>>>>> the dial.Dwight
>>>>> From: hilpert at cs.ubc.ca
>>>>>> ---snip---
>>>>>>
>>>>>> I like how the box says "As accurate as a slide-rule".
>>>>>>
>>>>>> Presumably it uses standard log pots, aka volume controls.
6 Mar
6 Mar
4:57 p.m.
New subject: Slide Rules
I recall a "spiral" slide rule in a round
cylindrical package also.
Done to extend the length of the scale but not the physical length of
the rule.
My father had [1] an Otis King, which is a helcial slide rule. I found
another one in a charityshop for a very low prince, of course I bought
it. I often show it to visitors, very few people outside my immediate
circle of friends can work out what it is used for.
And then there were the circular slide rules. Never used one.
I always thought those were a good idea since the 2 ends of the scale
(effectively 1 and 10) coincide. You didn't have to think about which
way to move the slide to ensure the answer was on-scale.
Were there ever slide rules made for bases other than 10 (say scales from
1 to 8 or 1 to 16)? Those little 'move the sliders with a stylus and hook
roudn for carry' adding machiens did esist for other bases. The octal and
hexadecimal oens showed up on Ebay a few years ago. Unfortuantely they
sold for about \pounds 500 each (due to their rarity) which was a lot
mroe that I would spaend on a curiousity
-tony
5:35 p.m.
New subject: Slide Rules
> I recall a "spiral" slide rule in a
round cylindrical package also.
> Done to extend the length of the scale but not the physical length of
> the rule.
In addition to the Otis Kings, there were Fullers, Thachers, Nestler
cylinders, and probably others.
Were there ever slide rules made for bases other than
10 (say scales
from 1 to 8 or 1 to 16)? Those little 'move the sliders with a stylus
and hook roudn for carry' adding machiens did esist for other bases. The
octal and hexadecimal oens showed up on Ebay a few years
ago. Unfortuantely they sold for about \pounds 500 each (due to their
rarity) which was a lot mroe that I would spaend on a curiousity
Octal and hex addiators? Neat, hadn't seen those.
De
7 Mar
7 Mar
3:24 p.m.
New subject: Slide Rules
> I recall a "spiral" slide rule in
a round cylindrical package also.
> Done to extend the length of the scale but not the physical length of
> the rule.
In addition to the Otis Kings, there were Fullers, Thachers, Nestler
cylinders, and probably others. Were there ever slide rules made for bases other
than 10 (say scales
from 1 to 8 or 1 to 16)? Those little 'move the sliders with a stylus
and hook roudn for carry' adding machiens did esist for other bases. The
octal and hexadecimal oens showed up on Ebay a few years
ago. Unfortuantely they sold for about \pounds 500 each (due to their
rarity) which was a lot mroe that I would spaend on a curiousity
Octal and hex addiators? Neat, hadn't seen those. From waht I rememeber they arre like the decimal
version, just with the
right number of slots on the slides. IIRC they had 2 sets of
'uutput
windows', one above and one below the entry area. The second ouytput was
the inverse of the first (so on the octal model 0<->7, 1<->6, etc)
-tony
6 Mar
6 Mar
7:12 p.m.
New subject: Slide Rules
On 03/06/2013 01:57 PM, Tony Duell wrote:
Were there ever slide rules made for bases other than
10 (say scales from
1 to 8 or 1 to 16)? Those little 'move the sliders with a stylus and hook
roudn for carry' adding machiens did esist for other bases. The octal and
hexadecimal oens showed up on Ebay a few years ago. Unfortuantely they
sold for about \pounds 500 each (due to their rarity) which was a lot
mroe that I would spaend on a curiousity
There are all sorts of useful gizmos that are little more than a stick
of wood with printing on it. A slide rule is a good example. Hanging
in my shop is a souvenir from a timber-cruising course I once took. It
allows you to measure DBH (diameter at breast height) and a sighting
scale to determine the height of a tree to the nearest 10 feet and then
a table to compute Scribner volume in board feet. Someone who saw the
scale in inches might mistake it for a yardstick--it does have an inch
scale on one edge.
Are there any similar sticks for, say, estimating the number of cards in
a punched-card deck?
--Chuck
5 Mar
5 Mar
7:34 p.m.
New subject: Slide Rules
On 5 March 2013 22:30, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Not me!. Assuming you mean pure water at normal atmospheric pressure I'll
ahve 273.15 for freezign and 373.15 for boiling.
[Grin] Well all right, yes, Kelvin is sensible in a way. Zero is
really zero. OTOH, I very rarely have any use for temperatures much
below zero or much above 100, so the 0-to-100 decimal scale suits me
very well. Having a more sensible one that measures temperatures I
never need to measure is of limited utility to me.
--
Liam Proven ? Profile: http://lproven.livejournal.com/profile
Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven
MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven
Tel: +44 20-8685-0498 ? Cell: +44 7939-087884
10:04 p.m.
New subject: Slide Rules
> Not me!. Assuming you mean pure water at normal
atmospheric pressure I'll
> ahve 273.15 for freezign and 373.15 for boiling.
On Wed, 6 Mar 2013, Liam
Proven wrote:
[Grin] Well all right, yes, Kelvin is sensible in a
way. Zero is
really zero. OTOH, I very rarely have any use for temperatures much
below zero or much above 100, so the 0-to-100 decimal scale suits me
very well. Having a more sensible one that measures temperatures I
never need to measure is of limited utility to me.
Seems like I NEVER seem to need to care about temperatures below
0 Kelvin, nor even Rankin!
And, this year, right here, it didn't get below 0 Fahrenheit, Celsius, nor
even Centigrade.
Definitely Somebody Else's Problem.
--
Grumpy Ol' Fred cisin at xenosoft.com
6 Mar
6 Mar
12:41 a.m.
New subject: Slide Rules
On Tue, 5 Mar 2013, Fred Cisin wrote:
Have you ever read Ray Bradbury's other book, "Fahrenheit -459.6"?
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
> Not me!.
Assuming you mean pure water at normal atmospheric pressure I'll
> ahve 273.15 for freezign and 373.15 for boiling.
On Wed, 6 Mar 2013, Liam
Proven wrote:
[Grin] Well all right, yes, Kelvin is sensible in
a way. Zero is
really zero. OTOH, I very rarely have any use for temperatures much
below zero or much above 100, so the 0-to-100 decimal scale suits me
very well. Having a more sensible one that measures temperatures I
never need to measure is of limited utility to me.
Seems like I NEVER seem to need to care about temperatures below
0 Kelvin, nor even Rankin!
And, this year, right here, it didn't get below 0 Fahrenheit, Celsius, nor
even Centigrade.
Definitely Somebody Else's Problem.
9:44 a.m.
New subject: Slide Rules
Actually, they could have tied temperature to a measurementof distance using the gas law
and absolute.That would have made better sense.Dwight
4152
days inactive
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38 comments
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ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
cisin＠xenosoft.com -
dgriffi＠cs.csubak.edu -
dkelvey＠hotmail.com -
drb＠msu.edu -
hilpert＠cs.ubc.ca -
jws＠jwsss.com -
jwsmail＠jwsss.com -
lproven＠gmail.com -
mcguire＠neurotica.com -
mtapley＠swri.edu -
thrashbarg＠kaput.homeunix.org