OT: Engineers

Ray Andraka ray@andraka.com posted to sci.electronics.design:

> Richard Owlett wrote:
>
>>>
>>
>> Real engineers know what a Log Log Duplex Decitrig is and how to
>> use it.
>>
>
> Are there any of those left anywhere???

I am still around. I still have one. How about you?

Top right hand drawer. Scare the $#!t out of some freshman students when I
pull that sucker out and start doing problems with it.

Jim

--
"If you think you can, or think you can't, you're right."
--Henry Ford

"Ray Andraka" <ray@andraka.com> wrote in message
news:ADgLi.290336$BX3.174538@newsfe13.lga...
> Richard Owlett wrote:
>
>>>
>>
>> Real engineers know what a Log Log Duplex Decitrig is and how to use it.
>>
>
> Are there any of those left anywhere???

My yf got me one for my 40th birthday. It is sold under the name "shadow
box". She had our local PCB shop do the nameplate with ink stenciled over
gold flash pc board.

Jim


I need to get some sort of case with the
> label "In case of emergency, break glass".
>

"Jerry Avins" <jya@ieee.org> wrote in message
news:irCdnWnA15Qi0mPbnZ2dnUVZ_jednZ2d@rcn.net...
> Philip Martel wrote:
>> "Jerry Avins" <jya@ieee.org> wrote in message
>> news:zf-dnehkEpn7BmDbnZ2dnUVZ_rninZ2d@rcn.net...
>>> Philip Martel wrote:
>>>> "Ray Andraka" <ray@andraka.com> wrote in message
>>>> news:ADgLi.290336$BX3.174538@newsfe13.lga...
>>>>> Richard Owlett wrote:
>>>>>
>>>>>> Real engineers know what a Log Log Duplex Decitrig is and how to use
>>>>>> it.
>>>>>>
>>>>> Are there any of those left anywhere???
>>>> Sure:
>>>> http://www.antiquark.com/sliderule/s...lide-rule.html
>>> That's a blown-up [interactive] image of the little 6" rule I sometimes
>>> keep in my jacket pocket! Hot diggety! Thanks.
>>
>> If you click on the [Gallery Index] link at the top, you can get seven
>> different slide rules. After I found this page, I hunted around some
>> more. I found a few other similar pages, including IIRC a circular slide
>> rule.
>>
>>>> :-)
>>>>
>>>> Actually, I have a physical one underneath my computer desk.
>>> Phil, I'm afraid we're a dying breed.
>>
>> I'm a few years younger than you. If I had gone to school a few years
>> later, I'd have been able to get an SR-50, and probably wouldn't remember
>> how to use a slipstick. As it was, I took a course in how to construct
>> Nomograms and eventually did may Master's thesis on a digital
>> implementation of nomograms.
>
> Phil,
>
> Do you know how the minute and second marks on the ST scale are used? I've
> forgotten. It's clear that they're 6 (60) apart. The R mark on the C and D
> scales eludes me too, but I never used that. (The manual got lost in a
> move years ago.)
>
> Jerry

Jerry,

I thought it the marks would correspond to the sine of one minute and one
second. That seems to be the case on my Sterling, but it's obviously not
the case on the N600. I spent a bit of time hunting around on the web for
an online manual - no luck, but I did find out that the R mark corresponds
to the number of degrees in a radian, 57.3, so you can use it to find sines
and tangents of small angles...

I fooled around for a few more minutes. If you put the minute mark on the
ST scale over the 1on the D scale, the 10 on the C scale is over 2.91, which
corresponds to the sine of 1 minute, 2.908E-4. Similarly for the second
mark. So placing the mark over the 1 takes a number of minutes on the C
scale to its sine on the D scale.

Best wishes,
--Phil
> --
> Engineering is the art of making what you want from things you can get.
> ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

RST Engineering (jw) wrote:
> Top right hand drawer. Scare the $#!t out of some freshman students when I
> pull that sucker out and start doing problems with it.

A log-log rule makes a handy dandy wire table. Using a calculator for
that is a pain.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

RST Engineering (jw) wrote:
> My yf got me one for my 40th birthday. ...

So yf is the new xyl?

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

Philip Martel wrote:

...

> Jerry,
>
> I thought it the marks would correspond to the sine of one minute and one
> second. That seems to be the case on my Sterling, but it's obviously not
> the case on the N600. I spent a bit of time hunting around on the web for
> an online manual - no luck, but I did find out that the R mark corresponds
> to the number of degrees in a radian, 57.3, so you can use it to find sines
> and tangents of small angles...
>
> I fooled around for a few more minutes. If you put the minute mark on the
> ST scale over the 1on the D scale, the 10 on the C scale is over 2.91, which
> corresponds to the sine of 1 minute, 2.908E-4. Similarly for the second
> mark. So placing the mark over the 1 takes a number of minutes on the C
> scale to its sine on the D scale.

Thanks, Phil. Now that you mention it, I vaguely remember what you write
about the R mark. Note that if the ' mark in over the 10 on the C scale,
the " mark is over the 6. Good sleuthing!

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

In article <IqKdnWrSX-oWi2LbnZ2dnUVZ_oPinZ2d@rcn.net>, Jerry Avins wrote:
>RST Engineering (jw) wrote:
>> Top right hand drawer. Scare the $#!t out of some freshman students when I
>> pull that sucker out and start doing problems with it.
>
>A log-log rule makes a handy dandy wire table. Using a calculator for
>that is a pain.

One way to put almost half of this in your brain adequately for a lot of
design work, especially for "magnetic components":

Remember the 10 "third octave numbers" and the 10 in-between "1/6 octave
numbers".

The "third octave numbers" are the ten powers of the 10th root of 10.
The other ones are the odd powers among the first 20 of the 20th root of
10.

Multiply two "third octave numbers", you get another.

Raise a "third octave number" to any whole number power, you get another
one.

Square root of a "third octave number" is always a "1/3 octave" or a
"1/6 octave" one.

Does not take too long when trying for this system to figure out which.

Also helps for this system: 2 is close enough to 10 to the .3 power.
And pi is close enough to 10 to the .5 power.
And, AWG wire diameters, at least from low single digits to the
mid-upper 40's, are 1/3 and 1/6 octave numbers both in inches and metric.
Both cross section areas and squares of diameters are close enough to 1/3
octave numbers in both inches and metric. Ratio of feet of wire length to
ohms is close enough to a 1/3 octave number at 20 degrees C, and another
one at 100 degrees C. Ratios of meters of wire length to ohms are close
enough to 1/3 octave numbers at 90 degrees C here.

Of course this system fudges things easily by up to a few, maybe several
percent. But for back-of-the-envelope calculations, calculating when you
got in a calculating mood when a calculator is not handy, and checking if
a calculator (or slide rule for that matter) was not mis-operated, this
works well.
This came in handy a lot for me for filter designs and some loudspeaker
enclosure designs. Sadly, electronic component values tend to have 12
increments (of "10% tolerance values") rather than 10 per decade, and 24
increments (of "5% tolerance values") rather than 20 per decade.
But if I round componet values in my head to the nearest "1/6 octave
numbers", I do get ballpark numbers! In that case I also keep track of
roughly what percentage off which way I rounded - correct answer for that,
and then I tend to get within a few percent. Makes great conversation if
a discussion at a bar or a restaurant gets to port/duct dimensions in a
tuned-port loudspeaker design, or design of a gapped inductor or a gapped
transformer!

- Don Klipstein (Jr) (don@misty.com)

On Sun, 16 Sep 2007 19:47:29 GMT, Rich Grise <rich@example.net> wrote:

>On Sat, 15 Sep 2007 21:23:39 +0000, VelociChicken wrote:
>> "HardySpicer" <gyansorova@gmail.com> wrote in message
>
>>> In north America I am led to believe, an engineer is a train driver.
>>> How do you distinguish yourselves if you live there from such an
>>> occupation? If you say you are an engineer do people then ask which
>>> line you serve on?
>>
>> An engineer is someone who works on engines.
>
>Like Babbage's "Numerical Engine"? ;-)
>
>Cheers!
>Rich

Hi,
speakin' of Babbage:

Charles Babbage wrote:

"On two occasions I have been asked [by members
of Parliament!], "Pray, Mr. Babbage, if you put
into the machine wrong figures, will the right
answers come out?"

I am not able rightly to apprehend the kind of
confusion of ideas that could provoke such a question."

See Ya',
[-Rick-]

D from BC wrote:

>
> Reverse Engineering Engineers could be Buccaneer Engineers.
> http://en.wikipedia.org/wiki/Buccaneer
> D from BC


Buckanear Engineers design overpriced corn.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida