| 摘要 |
PURPOSE:To compensate temperature exactly by providing two pyroelectric elements, two diodes, which are reversely connected to each other in parallel between output electrodes of the said elements, and one operational amplifier in which outputs of the said elements are fed to its input terminal and by which the sum of said inputs is provided as its output. CONSTITUTION:When the infrared rays 21, 31 with the same intensity, which are emitted from the same object, are applied to the pyroelectric elements 22, 32, voltages, which are positive-negative symmetric with each other and values of which are equal to each other, are developed at the capacitors 51, 52. When these voltages are applied to the positive and negative side inputs of the operational amplifier 59 through the resistor 55, 57 respectively, the sum of these voltaes can be obtained at the output terminal 60. When the switches 53, 54 are closed to connect the circuit directly, a greater signal is developed as the sum of logarithmic compression. In this way, since temperature is cimpensated by the diodes 29, 30, which are reversely connected to each other in parallel between the electrodes 24, 34 and the sum of both outputs is obtained through the operational amplifier 59, the output can be obtained as the sum of logarithmic compression simply. |
