David Brian Witt

US Patent:

6404324, Jun 11, 2002

Filed:

Sep 7, 1999

Appl. No.:

09/453047

Inventors:

David B. Witt - Fishers IN
Scott E. Crawford - Indianapolis IN

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H01C 1014

US Classification:

338320, 338309, 338322, 338328, 338 50, 338 59

Abstract:

A resistor having a generally planar substrate with a resistive element located on each side of the substrate and a plurality of terminals for connecting opposing portions of each of the resistive elements to an electronic circuit. The resistive elements have substantially equal dimensions and resistive properties such that they have substantially equal resistance values and exhibit substantially equal current densities for any given applied voltage. The substrate can be a ceramic-coated metal core with the resistive elements silk-screened onto opposite sides of the substrate. The resistive elements have a substantially uniform thickness so that they exhibit a uniform current density when subjected to an applied voltage. With this dual resistive layer design, thermal bending of the resistor due to differential thermal expansion at one of the ceramic layers is substantially offset by thermal bending due to differential thermal expansion at the other ceramic layer. Accordingly, the resistor can be designed with a small physical size and a relatively low steady-state wattage rating, but with the ability to handle short duration, high-wattage power surges.