Sensitivity Enhancement of Wheatstone Bridge Circuit for Resistance Measurement

• Main Authors: Tarikul ISLAM, Shakeb A. KHAN, Sheikh S. ISLAM, HARSH
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2009-08-01
• Series: Sensors & Transducers
• Subjects: Resistive sensor; Wheatstone bridge; Active bridge; Sensitivity enhancement; Temperature effect; Lead resistance
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/august_09/P_SI_75.pdf

Present work deals with the development of a low cost, appreciably accurate and sensitive electronic circuit for resistive sensor. The circuit is based on the modification of the Wheatstone bridge using active devices. It helps measurement of the incremental resistance precisely and linearly. It requires few components for its hardware implementation and found to be suitable in case there is small change in resistance due to change in physical quantity or chemical analytes to be measured. Theory of the proposed bridge circuit has been discussed and experimental results have been compared with conventional full bridge circuit. Experiments have been conducted with metallic strain gauge sensor but it can be utilized to other resistive sensors. Results show that the output of the circuit is almost four times more than usual full Wheatstone bridge circuit. Experimental results show that the errors due to the effects of the ambient temperature and connecting lead resistance are minimized.