Aspects of Signal Condition from DC Bridge Circuits

Sensors based on the variation of the electric resistance are very common. There are many mechanisms that can modify the electric resistance of a material and also many signal conditions for resistive sensors. However, Wheatstone bridge measurement method is often used to measure unknown electrical resistance. This paper examined with the application of signal condition for very small change of resistance. The tests were performed by a model with deformation unit which consists of two semiconductor strain gauges situated in two axes . The outputs of bridges are connected into new special circuits which are distinguishable from operational and instrumental amplifier. The results according to the accuracy and uncertainty are played very positive quality for instrumentation amplifier. There is advantage to use only one am-plifier and only one resistor as extern element for amplifying in the range from 1 to 10000 with minimum offset and temperature drift. The survey confirmed that high accuracy, stability and minimal uncertainty of bridge circuit measurement is with instrumental amplifier and the circuit is very suitable as an intermediate stage between sensors and analogue inputs for microcontrollers