Dual sensor for detecting oxidising and reducing harmful gases near motor vehicles

摘要

The sensor comprises two sensor elements (S1,S2). The signals are tapped at each of the two voltage dividers (TP1,TP2), and supplied as voltages to the input of analogue control stages (R1,R2), assigned directly to the associated sensor elements across a decoupling stage formed by an impedance converter (IPW1,IPW2). The other inputs are connected to a common reference voltage source (Q1) serving to provide a desired voltage value. The outputs of the two regulating stages communicate with a variable on-chip resistance (RR1,RR2). By this means the other branch of one of the two voltage dividers is formed.