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#163785 - 05/16/07 06:42 PM Old DC Volt Meter (Yuasa)
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The firm I work for performs a variety of testing services. This picture is a DC volt meter full scale reading -3.0 to +3.0. Typical battery readings are 2.15-2.35 (float to equalize). The user has to be fast and familiar with the scale to read the numbers beyond the decimal point.

Now a days with digital meters apprentices often give us readings into the 1000s of a volt, which is really not necessary. We have to tell them just because you can obtain some data it is not always necessary.

- BGaquin (Brian)

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#163791 - 05/17/07 05:43 AM Re: Old DC Volt Meter (Yuasa) [Re: Admin]
ghost307 Offline
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Registered: 05/09/05
Posts: 900
Loc: Chicago Illinois USA
I agree; sometimes extreme accuracy is useless.
When I was taking science class in High School, we were working problems on a reflecting telescope.
One of the kids decided that his answer had to involve subtracting the mirror's 12" focal length from the distance to the object that was being observed.
Unfortunatly for him, it was the SUN!
There's something very silly about subtracting 12" from 93 million miles in the name of accuracy.
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#163792 - 05/17/07 06:50 AM Re: Old DC Volt Meter (Yuasa) [Re: Admin]
BGaquin Offline
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Registered: 05/08/03
Posts: 14
Loc: Sterling, VA
But as the folks at NASA will tell you just make sure you both are measuring in Meteric or the US Standard.
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#163796 - 05/17/07 10:27 AM Re: Old DC Volt Meter (Yuasa) [Re: BGaquin]
ghost307 Offline
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Registered: 05/09/05
Posts: 900
Loc: Chicago Illinois USA
Picky...picky...picky

Ya run into ONE planet and nobody will ever let you live it down...
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#163797 - 05/17/07 11:17 AM Re: Old DC Volt Meter (Yuasa) [Re: ghost307]
wa2ise Offline
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Registered: 11/29/02
Posts: 782
Loc: Oradell NJ USA
At least they FOUND the planet!... :-)
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#163964 - 05/21/07 05:03 PM Re: Old DC Volt Meter (Yuasa) [Re: Admin]
Bjarney Offline
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Registered: 04/10/02
Posts: 2527
Loc: West-Southern Inner-Northeast ...
 
The meter looks like it has a narrow mirror below the scale graduations. What is that for?
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#163965 - 05/21/07 05:41 PM Re: Old DC Volt Meter (Yuasa) [Re: Bjarney]
LarryC Offline
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Registered: 07/05/04
Posts: 780
Loc: Winchester, NH, US
Quote:
The meter looks like it has a narrow mirror below the scale graduations. What is that for?


When the needle image in the mirror is at its narrowest, you know you are perpendicular to the needle and therefore you have no parallax error.

If you look at the needle at a slant, the image location on the scale is either above or below the actual reading. That is called parallax. Many high resolution gauges and meters have the mirrored scales and the thin needle like pointers.
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