Re: Thermometer - Today's Math Challenge

Apr 06, 2009 3 Replies
M



> Stone cut face of outdoor thermometer has...
>
> 180° rotational degrees for 130°F temperature change.
>
> Bimetal thermometer element has...
>
> 180° rotational degrees for 90°F temperature change.
>
> Bimetal is 9-1/4 turns (labeled Truflex P675RTM2), inner diameter is
> 1/4", outer diameter is 1-1/16"
>
> How many (partial) turns to remove from outer bimetal to match
> physical requirement with bimetal movement ?:-)

Fix it in the software. OTOH, it would only be off by about 10% if you read it as C°. ;-)

And another motherboard bites the dust!
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A

It is a mechanical device, dipshit. You are off by far more than 10%.

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J

How do I move the dial, "in software" ?:-)

I guess the real "engineer" way to do it is to grab it with a small vise and run it in the oven, moving the support point until I get the right span. Bend a tab there and cut off the rest.

...Jim Thompson

| James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | "One experiment is worth a thousand expert opinions." -Wernher von Braun
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M

You got it. The metal is softer when its hotter. OTOH, if you get it too hot, and it'll turn into a puddle.

If you don't want to do it in software, use a thermistor, power op amp and a Peltier junction to correct the curve. :)

And another motherboard bites the dust!
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