| 摘要 |
PURPOSE:To simplify a circuit constitution and to prevent the malfunction, by comparing the output voltage of a sensor that delivers an external change in the form of the electric signal with the 1st and 2nd reference voltage values respectively and leading out the detection output of disconnection based on the result of comparison. CONSTITUTION:The plus power supply of a battery 33 is connected to an end (a) of a resistance 32 of a potentiometer constituting a sensor 31 via a resistance R1; and the minus power supply of a battery 36 is connected to the other end (c) via a resistance R3. A rubbing contact (b) is connected to a converting amplifier 34 including a buffer amplifier A2 as well as to a disconnection detecting part 35. The output voltages of buffer amplifiers A1 and A2 to which the potential change of a signal line L3 is supplied are compared with the 1st and 2nd reference voltage values V6 and V7 respectively by the plus and minus voltage comparators A3 and A4, These comparators A3 and A4 constitute the part 35. The disconnection detecting signals are led out through the output terminals of the comparators A3 and A4. |
