Howard P Layer

US Patent:

RE326313, Mar 29, 1988

Filed:

Jul 10, 1986

Appl. No.:

6/884728

Inventors:

Howard P. Layer - Derwood MD

Assignee:

Frazier Precision Instrument Company, Inc. - Gaithersburg MD
Holometrics, Inc. - Derwood MD

International Classification:

G01G 314
G01B 716
G01D 304

US Classification:

177211

Abstract:

The strain gauge bridge circuit located in. [. the. ]. . Iadd. a. Iaddend. load cell. [. of a load cell mass comparator. ]. is modified to provide temperature stability by coupling a remotely located temperature compensating circuit between the two normally connected output ends of strain gauges in adjacent arms of the bridge. The compensating circuit is comprised of a pair of series connected low noise, drift-free precision resistors of relatively low resistance value compared to the resistance of the strain gauges. The precision resistors are shunted by relatively high valued potentiometers which operate to balance the bridge. One potentiometer additionally includes a series connected high value precision resistor for providing fine balance while the other potentiometer is used for coarse balance.

US Patent:

45414963, Sep 17, 1985

Filed:

Mar 12, 1984

Appl. No.:

6/588219

Inventors:

Howard P. Layer - Derwood MD

Assignee:

Frazier Precision Instrument Company, Inc. - Gaithersburg MD
Holometrics Inc. - Derwood MD

International Classification:

G01G 314
G01L 122

US Classification:

177211

Abstract:

The strain gauge bridge circuit located in the load cell of a load cell mass comparator is modified to provide temperature stability by coupling a remotely located temperature compensating circuit between the two normally connected output ends of strain gauges in adjacent arms of the bridge. The compensating circuit is comprised of a pair of series connected low noise, drift free precision resistors of relatively low resistance value compared to the resistance of the strain gauges. The precision resistors are shunted by relatively high valued potentiometers which operate to balance the bridge. One potentiometer additionally includes a series connected high value precision resistor for providing fine balance while the other potentiometer is used for coarse balance.