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(11) | EP 0 055 331 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Method of trimming thin metal resistors |
(57) A thin metal film resistor (15) of a capacitative graphic tablet is trimmed to make
the resistor linear within about 0.25%. Alternating voltage is applied along the resistor
by a source (40). The resistance of the resistor is measured at discrete points by
a capacitative probe (34) and the resistance readings are stored in a data processor
(45). A profile is calculated in the processor from the stored readings and a trim
operation is made by an electro-erosion apparatus. |