| 摘要 |
PURPOSE: To provide an electron gain circuit in which an output signal of an amplifier is automatically adjusted in accordance with temperature variation by adjusting gain of the amplifier automatically according to variation of ambient temperature and adjusting gain of the amplifier to the temperature variation. CONSTITUTION: Taking an example in which a piezoelectric pressure converter 10 is connected to a gain circuit 5, a bridge is pressurized to measure the pressure. Piezoelectric elements 22, 28 have resistant value equivalent to constant resistance 34, 36 in zero relative pressure. Voltage of a node 26 is made equal to a half of power source voltage VCC by partial pressure action of the bridge. Voltage of the node 30 equals to a half of the power source voltage VCC as the element 28 and the resistance 36 are zero pressure and they have equivalent resistance value. Voltage of the node 30 increases when the resistant value of the element 28 increases. On the other hand, voltage of the node 30 decreases when the resistant value of the element 22 increases. Accordingly, the voltage of a node 46 decreases. Output voltage of a differential amplifier 54 in a node 64 is linearly increased by decreasing of the voltage of the node 46. |
