Questions tagged [metrology]
29 questions
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3 answers
How do you determine the accuracy of a measurement device?
Lets say you have a measurement device of which you do not know the accuracy, and a reference measurement device. Both measure a variable $x$. The range of interest is $x_0
JHK
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How to measure a laser diode's Wavelength
I have some laser diodes. I want to know how to measure the wavelength of laser diodes ranging from visible to near infrared? (300 nm to 1100 nm)
What type of instrument/meter do I need to use? spectrometer, spectrophotometer, wavelength meter,…
SARDAR TARIQ
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4
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1 answer
Uncertainty Calculation of LVDT displacement transducers for length measurement
I have to calculate the uncertainty of measurement for an LVDT Linear displacement transducer used for measuring length. Uncertainty calculations are ruled by ISO 17025 but there are no (at least haven't found) specific guidelines for the…
spe4ker
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3
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2 answers
Are there different Gauge standards out there?
It is my understanding that a mil is a one thousandth of an inch (1mil = 0.001”). Also, a mil is 25.4 microns, aka micrometers. Then, it is my understanding that Gauge is 100x mil (1mil-100Ga).
I am looking for some copper sheets for a project, and…
KingsInnerSoul
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3
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1 answer
What does "BSL Accuracy" mean?
An example is this pressure transmitter which has a BSL accuracy of 0.08%. I know the term "Best fit straight line" - BFSL. Is BSL just a short hand for this ("Best straight line")?
JHK
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3
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1 answer
Units for plasma etching of circuits: A (with degree symbol)/min
Background: I'm a statistician working with a design of experiments example regarding plasma etching of circuits, and unfortunately, the author does not define what is meant by the units used for the etch rate ($\mathring{A}$/min). A google search…
Meg
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3
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1 answer
Communicating losses and imprecision in liquid measurement by analogy
I'm writing a presentation for people and I need an analogy to convey the following problem:
Person A wants to sell a liquid, so he fills a tank, measures volume
and sends to Person B. Now Person B receives the liquid and wants to
know if he…
eri0o
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3
votes
2 answers
How to automatically process energy meter data considering outliers and meter reset?
I want to algorithmically process energy meter data. The energy meter measures a heat or power producer or a heat or power consumer (but not both, so the measured energy will always have a positive sign). No additional information is known about the…
Daniel
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3
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3 answers
Rule of Tens/Ten to 1 Rule in Measurement and Inspection
I'm trying to clarify my understanding about the requirements [read: best practices] for measurement resolution and measurement confidence.
The "Rule of 10s" is a commonly tossed around guideline for measurement resolution that, to the best of my…
Argonax
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3
votes
1 answer
Is a building story actually 10ft (3m)?
In common US usage, the heights of tall things are sometimes converted to a "number of stories". The thinking is that people can better compare heights to similar tall buildings that they might have seen.
The US conversion is…
hazzey
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3
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How does Rule-1 guarantee cylindriccity in GD&T?
If I have defined the size tolerance of a shaft, how is the maximum cylindricity tolerance automatically specified by rule-1 of GD&T?
I mean when a shaft shoulder diameter is defined (e.g. 33g6) then it is usually checked by measuring the diameters…
Abhishek
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2
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2 answers
How are perfectly square blocks made from scratch?
So I'm looking into how stuff is made from scratch, starting with a surface plate which has been lapped flat using the three plate method. But almost everything I read on the subject on "the history of precision" and such stops there and glosses…
Beacon of Wierd
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2
votes
1 answer
Dead weight pressure tester for very low positive pressures
Does the dead weight tester technology provide capability for an accurate, low pressure calibration standard in the range of zero to 150 cm H2O, and if so is there a manufacturer that provides such an instrument?
If not, what is the best primary…
docscience
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vote
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What is the name for a digital height measuring device?
What is the generic name of the electronic hand-held device that measures the relative height of two different points (altitude, etc.)?
As an example, suppose I'm climbing a tree. I turn on the device, put it in my pocket, and once I've climbed 15…
Pretty_Girl
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1
vote
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Mechanical drilling and Photolithography alignment front and back 1st layer alignment
I am new to the PCB manufacturing industry.
• Can a Plated through hole in a Copper pad represent a first-layer alignment post-lithography?
It isn't very clear to me.
• How does one measure the alignment of a drilling machine and a photolithographic…
Proto PCB
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