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--- tutorials:learn:calipers:index.html [2010/12/03 15:31]
daigo created
+++ tutorials:learn:calipers:index.html [2016/01/28 18:05] (current)
@@ Line 10: / Line 10: @@
-There are a few different types of caliper you'll come across: digital, dial and vernier. We're going to skip vernier and show the different between dial and digital.
+There are a few different types of caliper you'll come across: digital, dial and vernier. We're going to skip vernier and show the difference between dial and digital.
 [[http://www.ladyada.net/images/calipers/pinion.jpg|{{  http://www.ladyada.net/images/calipers/pinion_t.jpg?nolink&500x345  |}}]]
@@ Line 16: / Line 16: @@
-Dial calipers use a mechanical system consisting of a rack and pinion, there's a gearset inside as well that moves the dial in increments of one hundredth of an inch (or tenth of a mm). To read, the 'most significant' value is read from the rule and the fractional value from the dial. The nice thing about dial calipers is that they don't use batteries and although are not waterproof, work well even if damp.
+Dial calipers use a mechanical system consisting of a rack and pinion, there's a gear-set inside as well that moves the dial in increments of one thousandth of an inch (or hundredth of a mm). To read, the 'most significant' value is read from the rule and the fractional value from the dial. The nice thing about dial calipers is that they don't use batteries and although are not waterproof, work well even if damp.
@@ Line 32: / Line 32: @@
 [[http://www.ladyada.net/images/calipers/254mm.jpg|{{  http://www.ladyada.net/images/calipers/254mm_t.jpg?nolink&500x338  |}}]]
-So how does a digital caliper work even  gears? it turns out that undernear the plastic 'ruler' overlay is an engraved copper design. The slide part has a circuit board with thin strips that look like a 'comb'. The comb and copper pads form a grid of capacitors,[[http://en.wikipedia.org/wiki/Capacitor| two conductive plates separated by the dialectric plastic overlay.]] As the comb slides over the copper pattern, the capacitance between the plates changes. If the patterns are engraved precisely, even very small changes in capacitance can be detected by an analog interface (such as an RC timer or oscillator)
+So how does a digital caliper work without gears? it turns out that underneath the plastic 'ruler' overlay is an engraved copper design. The slide part has a circuit board with thin strips that look like a 'comb'. The comb and copper pads form a grid of capacitors,[[http://en.wikipedia.org/wiki/Capacitor| two conductive plates separated by the dielectric plastic overlay.]] As the comb slides over the copper pattern, the capacitance between the plates changes. If the patterns are engraved precisely, even very small changes in capacitance can be detected by an analog interface (such as an RC timer or oscillator)
-[[http://www.ladyada.net/images/calipers/capstrip.gif|{{  http://www.ladyada.net/images/calipers/capstrip_t.gif?nolink&500x334  |}}]] \\ [[http://www.flickr.com/photos/50241702@N04/5227386500/|//Photo from PhysicDude//]]
+[[http://www.ladyada.net/images/calipers/capstrip.gif|{{  http://www.ladyada.net/images/calipers/capstrip_t.gif?nolink&500x334  |}}]] \\
+<class center>[[http://www.flickr.com/photos/50241702@N04/5227386500/|Photo from PhysicDude]]</class>
 This means that if the dielectric changes it can mess up the readings. For this reason, digital calipers can give jumpy readings if they are dirty or wet.
@@ Line 44: / Line 45: @@
-Keep your calipers happy and safe in their box. Even though digital calipers are in many ways more durable than mechanical/dial types, espcially with respect to shock, when traveling or storing, keep 'em in the case!
+Keep your calipers happy and safe in their box. Even though digital calipers are in many ways more durable than mechanical/dial types, especially with respect to shock, when traveling or storing, keep 'em in the case!
@@ Line 56: / Line 57: @@
-To replace the battery, just snap of the top cover, the battery is **44 **size 1.5V alkaline button battery, available in any hardware or grocery store.
+To replace the battery, just snap of the top cover, the battery is **LR44/SR44 **size 1.5V button battery, available in any hardware or grocery store. The Silver Oxide SR44 costs more, but will last longer.
@@ Line 74: / Line 75: @@
-The first measurement is using the 'outer' jaws. Use the flat part if possible, to avoid any skewing. Use the thumbwheel to get a good tight grip on the material. You'll not ites not exactly 20mm, that's from the manufacturing tolerances, not the calipers.
+The first measurement is using the 'outer' jaws. Use the flat part if possible, to avoid any skewing. Use the thumb-wheel to get a good tight grip on the material. You'll not3 it's not exactly 20mm, that's from the manufacturing tolerances, not the calipers.
 [[http://www.ladyada.net/images/calipers/outer.jpg|{{  http://www.ladyada.net/images/calipers/outer_t.jpg?nolink&500x333  |}}]]
@@ Line 82: / Line 83: @@
 [[http://www.ladyada.net/images/calipers/inner.jpg|{{  http://www.ladyada.net/images/calipers/inner_t.jpg?nolink&500x388  |}}]]
-The last basic measurement is depth, often used for drilled holes. This measurement uses the gauge at the end of the calipers. You'll want to practive how to hold the calipers to push the tapered end piece down while also keeping the tail flat against the work, its a little counterintuitive!
+The last basic measurement is depth, often used for drilled holes. This measurement uses the gauge at the end of the calipers. You'll want to practice how to hold the calipers to push the tapered end piece down while also keeping the tail flat against the work, its a little counter intuitive!
 {{  http://www.ladyada.net/images/calipers/depth_t.jpg?nolink&500x353  |}}
-==== Step & relative measument  ====
+==== Step & relative measurement  ====
-Say we have a mint tin that we're measuring. We want to know the thickness of the metal, but because of the rolled edges, theres no easy way for us get a good measurement with the outer-pincers. However, we can use two measurements and subtract them! This is what digital calipers are good at.
+Say we have a mint tin that we're measuring. We want to know the thickness of the metal, but because of the rolled edges, there's no easy way for us get a good measurement with the outer-pincers. However, we can use two measurements and subtract them! This is what digital calipers are good at.
@@ Line 116: / Line 117: @@
-For example, on this 37-pin FPC (flex circuit board) I'm measuring between the center points (as far as I can manange) of the two outer pins.
+For example, on this 37-pin FPC (flex circuit board) I'm measuring between the center points (as far as I can manage) of the two outer pins.
 [[http://www.ladyada.net/images/calipers/tftpitch.jpg|{{  http://www.ladyada.net/images/calipers/tftpitch_t.jpg?nolink&500x337  |}}]]

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