| 摘要 |
PROBLEM TO BE SOLVED: To detect even the shortcircuiting state of a sensor by limiting to a small current value at the time of normal sensor, and limiting to a large current vale if it arrives at the current value near the short-circuiting state. SOLUTION: An acceleration sensor 1 varies the resistance value in response to an acceleration so that a resistance value is several in a steady state and can detects the presence or absence of the acceleration when the acceleration becomes a predetermined value or more so that the resistance value becomes 0. In this case, heretofore, since the A-D converted value alters like that the resistance of the sensor 1 becomes small when a power source voltage drops, V is employed as a power source 2, and a current limiter 3 which operates as a constant current source is provided. A controller 3 limits to a small current value at the time of normal sensor and limits to a large current value in the case of near short-circuiting state or the case that the voltage to the sensor 1 becomes low. A sensor voltage detector 4 fetches the voltage to the sensor 1, A-D converts it by an A-D converter 5, and outputs it to a microcomputer. Thus, the short-circuiting state of the sensor 1 can be detected. |
