Comparator: the relative method using measurement tools to measure the length of the micrometer and mainly by the comparator block form. Measurement, the first block of the amount of basic research have formed and measured the amount equal to the block group size, then the amount of block group to micrometer pointer to zero, then put on the workpiece, micrometer pointer indicates the size of the deviation is measured. micrometer used by the amplification principle, Comparator comparator can be divided into mechanical, optical Comparator comparator and three kinds of electrical mechanical comparator and the dial indicator and dial gauge, gear lever torsion spring micrometer or micrometer, etc. instruction sheet as a mechanical amplification, indicating parts. micrometer gear lever device works with dial indicator and dial gauge are similar, but the first one is the lever amplification mechanism, the indexing value is typically 1 micron. micrometer is a torsion spring with friction and without mechanical amplification mechanism of instruction sheet [ torsion spring micrometer works]. Its main component is an amplification from one end to the right from the middle of distortion, the other side of the left twisted metal sheet (width of about 0.1 mm, thickness of 0.005 millimeters), known as the twist spring wire in the middle of it stick with a diameter of about 0.06 mm hollow glass do pointer when measured under the rod moves, up and down displacement of the movable stand around converted to displacement, shortening or elongation of the torsion spring wire, and turn a pointer driven perspective, can be read from the dial on the measuring rod of the displacement. torsion spring micrometer sensitivity is high, a common scale value of 1 micron, 0.5 micron, 0.2 micron and 0.1 micron types, the highest up to 0.02 micron. indication range is typically ± 50 sub-scale value. mechanical comparator used in the workshop and the measurement chamber and thickness measurement of workpiece diameter. 
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