| 摘要 |
PURPOSE:To make it possible to perform reset operation per tare by an analog signal and to implement general purpose applications, by providing an operational amplifier device, which obtains the difference between the voltage at a connecting point of a switch and a capacitor that are connected in series between an input terminal and the ground, and an input voltage. CONSTITUTION:A resistor 7, a reset switch 8, and a capacitor 9 are connected to the output terminal of a first operational amplifier 6, which receives an input voltage Vi. An operational amplifier device 10 is constituted by operational amplifiers 11 and 12 and resistors 13-16. The voltage at the connecting point of the switch 8 and the capacitor 9 is inputted to the amplifier 12 through the amplifier 11. The output voltage of the amplifier 6 is directly inputted to the amplifier 12 through the resistor 7. The switch 8 is turned ON and the capacitor 9 is charged. The specified values of the resistors 13 and 14 are selected and the output voltage V0 of the device 10 is made to be zero. After the switch 8 is turned OFF, the voltage Vi is changed. Then the amount of negative change becomes the voltage V0. |
