| 摘要 |
PURPOSE:To detect securely whether a heat body is present or not by adjusting the identification level to a comparator to a half as large as the peak value obtained by converting infrared rays from the heat body photoelectrically. CONSTITUTION:The detection signal Vi obtained by converting the infrared rays from the heat body photoelectrically is branched; one is supplied as an input signal to the comparator 1 and the other is voltage-divided by resistors 2 and 3 which are equal in resistance value and supplied to a terminal (a) of a switch 5 through a voltage follower circuit 4, thereby displaying a signal whose level is a half as high as the peak value of the signal Vi on a meter 6. The identification level which is the other input signal to the comparator 1 is supplied from a reference voltage source 7 to a terminal (b) of the switch 5 through a potentiometer 8 and then the switch 5 is closed to the signal of the terminal (b), thereby displaying the level on the meter 6. The potentiometer 8 is adjusted so that the level is a half as high as the peak value of the signal Vi. Therefore, the identification level is easily adjusted to an optimum value when background light, heat body temperature, or the amount of steam, etc., vary, thereby detecting securely whether the heat body is present or not. |
