What is a decade resistor box useful for?

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I see these devices around, but have never really seen the value of them.

Is the whole appeal that they act like a variable resistor with really fine resolution and massive range? Or is there something important that I'm missing? I love how some of the devices look - but I just don't know why I need one!

Thanks!

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Quote:
they act like a variable resistor with really fine resolution and massive range?
Correct, but I have never needed one either. :-)

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Quote:

I love how some of the devices look - but I just don't know why I need one!

Your Certified Geek Diploma is in the mail.. :wink:

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I wish I had one. Resisting the decades starts to sound very attactive at my age.

Four legs good, two legs bad, three legs stable.

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LOL, John!

Yes, massive range sounds good. Not really a pleasant thing to think about, but I suppose a fine resolution is preferable just before being put in that box.

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"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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I think they partly date from a time when 1% resistors
were not that cheap and easiliy obtainable.

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Particularly handy if you deal with analog stuff like strain gauges.

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Not much.

Dad's lab at the college had stacks of them. When I was little I played with the knobs. When I was in college, they were all stacked in a cabinet and we never touched them.

Decade resistance? Careful! Birthdays are very important. Everyone who has died, died within a year of their last birthday! Don't stop having birthdays.

The largest known prime number: 282589933-1

In my humble opinion, I'm always right. 

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Everyone who has died, died within a year of their last birthday! Don't stop having birthdays.

The logical conclusion of that is that you need to celebrate your birthday more than once a year. The theoretical expected value is that you will die on average 365.25/2 days after your last birthday. Furthermore, the distribution is likely not a classic statistical "bell distribution" around that date, but rather probably something close to an even distribution. I'd expect the even distribution to be modified mainly by things not directly associated with your day of birth, e.g. season.

So, for a 10 percent likelihood of eternal life, you'd need to celebrate your birthday every 36 days or so. :D

OTOH, that amount of cake and booze will likely drive you into a malign cardiovascular condition eventually.

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No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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I have a very, very old decade box that I bought from my university when they were upgrading the lab equipment. The last time I used it was to check the linearity of a programmable constant current source that I had designed... 22 years ago. Maybe I need to have an upgrade too :lol:

Ross McKenzie ValuSoft Melbourne Australia

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Careful! Birthdays are very important. Everyone who has died, died within a year of their last birthday! Don't stop having birthdays.

Not sure that I thoroughly understand that - it would seem to be safer NOT to have birthdays, but it reminds me of the old joke about the Irishman/blonde/Newfie/Pole/Norwegian/Martian/social worker/politician/banker(whichever offends you least) who read that most road accidents happen withing half a mile of home, so they moved house.

Four legs good, two legs bad, three legs stable.

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Precision, calibrated Resistance Decade Boxes are commonly used for calibration and surveillance testing of industrial process monitoring equipment.

Most often to simulate RTDs (resistance temperature detectors) and conductivity monitors.

The cal lab maintained nearly 40 of these from GenRad and General Resistance. These are generally calibrated to 0.01% of Reading, required a disproportionate time resource when calibrated with a bridge.

For non-precision Resistance Substitution Boxes - their time seems to be long past.

Stan

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Quote:
it would seem to be safer NOT to have birthdays
That's my take, maybe celebrate one every 100 years or so.....

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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I plan on using a decade box to figure out what type of temperature sensor I need for a temperature gauge in my kit car. I will record the resistance values for a few temperatures, then see if it matches NTC, or other sensor characteristics.

It all starts with a mental vision.

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Ditto to what sbennett said. I have couple Leeds & Northrup boxes I use daily. Both getting close to 100 years old and ridiculously accurate.

Tom Pappano
Tulsa, Oklahoma

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The galvometer and leyden jars still good as well?

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Quote:

Most often to simulate RTDs (resistance temperature detectors) and conductivity monitors.


Quote:

Ditto to what sbennett said.

We don't use them daily, but it isn't unusual for us to have one hooked up to prototype/DUT setups of our industrial controllers. It lets you test the e.g. conductivity measurement circuit through its range. Also to simulate the operation of an app cycle.

Still accurate, but generally we don't care about lab-quality calibration levels. They
are "close enough".

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The galvometer and leyden jars still good as well?

I have several portable potentiometers that I use frequently that have galvanometers and standard cells. One of them that still works just fine, was last calibrated in 1929 8-)

Tom Pappano
Tulsa, Oklahoma

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tpappano wrote:
Quote:
The galvometer and leyden jars still good as well?

I have several portable potentiometers that I use frequently that have galvanometers and standard cells. One of them that still works just fine, was last calibrated in 1929 8-)

By Thomas A Edison no doubt...

Ross McKenzie ValuSoft Melbourne Australia

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Kartman wrote:
The galvometer and leyden jars still good as well?

Igor! We need more power! Capture more lightning! :mrgreen: