Temperature compensating circuit null for semiconductor strain gauge

摘要

PURPOSE:To enable adjustment of a compensation value on the high and low temperature sides to different values independently and continuously, by connecting two variable resistors in parallel between output terminals of a bridge circuit. CONSTITUTION:This circuit is provided with a bridge circuit 2 containing a semiconductor strain gage, a sensitivity temperature compensating circuit 1 for compensating temperature for the sensitivity by driving the circuit 2, a zero-point temperature compensating circuit 3 which generates a voltage almost equal to the potential of an output terminal of the circuit 2 when the circuit 2 is at a specified temperature. Two variable resistors R35a and R35b are connected in parallel between output terminals (b) and (d) of the circuit 2 and it is so arranged that slide elements of respective resistors R35a and R35b are connected to a connection point (e) of the circuit 3 alternatively through a switch circuit 5 having two switches adapted to make an ON action alternatively according to the variations in the resistances R34a and R34b and the temperature. Thus, positive and negative compensation values can be varied continuously.