| 摘要 |
PURPOSE:To enable high-resolution detection over a wide detection range by inputting the output of a field effect transistor(FET) to plural amplifying circuits which differ in amplification gain by the semiconductor sensor, and obtaining plural detection outputs. CONSTITUTION:When the FET 2 is stressed, the drain current ID of the FET 2 varies and this variation is applied to a current-voltage converting circuit 3 to generate a voltage output 3e, which is sent to 1st and 2nd amplifying circuits 4 and 5. The circuit 5 is set in voltage gain lower than the circuit 4. The output 4b of the circuit 4 is supplied by a switch circuit 9 to a selection output terminal 6c in a range wherein the stress applied to the FET 2 is weak. When the stress is large, the output 7a of a comparator 7 which monitors the output level of the circuit 5 goes up to an H level and the circuit 9 is switched to a dotted-line side through a timer circuit 8 to supply the output 5b of the circuit 5 to the terminal 6c. Consequently, a high-resolution detection output is obtained over a wide range from a fine input to a large input. |
