Precision variable resistor
AssigneeVishay Israel Ltd.
InventorsJoseph Szwarc, Jean-Michel Lanot, Felix Zandman
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Abstract
On the track of a potentiometer a resistive path of thin film is deposited or a foil is bonded to a matched substrate and a parallel path is formed of discrete contact straps extending from the resistive path. The resistive path has a protecting coating and the wiper is moving on abrasion resistant contact straps. This design enables application of high precision and stability resistor technologies in the production of variable resistors destined for long service life. It enables also, in high precision applications, by maintaining the linearity of the output versus input function, a two-wire connection to the variable resistor used as a position sensor.
Claims21
A precision variable resistor including a track, two terminal pads respectively connected one at each end of the track, the precision variable resistor comprising a plurality of contact straps extending along said track between said terminal pads, wherein said track and said contact straps are made of a precision resistive layer, forming a resistive path, said resistive layer is attached to a substrate, wherein said contact straps have insignificant electrical resistance as compared to the track and has a high abrasion resistance;
- wherein said contact straps operatively provide an electrical connection between a wiper and different locations along said resistive path during movement of said wiper on said contact straps;
- and wherein said resistive material has resistance versus temperature characteristic, as defined by the temperature coefficient of resistance (TCR), of less than 50 parts per million per degree centigrade (ppm/[deg.]C) and an end of life stability of at least 1%.
(canceled)
A precision variable resistor including a track with a first end coupled to a first terminal pad and a second end coupled to a second terminal pad, the precision variable resistor comprising:
- a plurality of contact straps extending between said first and second terminal pads, wherein said contact straps comprise a precision resistive layer and form a resistive path and wherein said contact straps have insignificant electrical resistance as compared to the track;
- and
- a wiper movably coupled to said plurality of contact straps, wherein said contact straps operatively provide an electrical connection between said wiper and locations along said resistive path during movement of said wiper on said contact straps,
- wherein said precision resistive layer has a resistance versus temperature characteristic, as defined by the temperature coefficient of resistance (TCR), of less than 50 parts per million per degree centigrade (ppm/[deg.]C) and an end of life stability of at least 1%.
Dependencies are inferred from the claim text.