| 摘要 |
PURPOSE:To make possible the display of percentage of moisture content by the pointer of the same scale irrespective of the kind of grain, by varying the resistance value of resistor connecting with the electrode for detecting the degree of moisture in accordance with the kind of grain. CONSTITUTION:One side of the electrode A is connected with the plus power source +V and the other side is connected with the amplifier B. The resistors R1- R5 are connected with the source +V freely switching by the switch S through the diode D and moreover, the variable resistor VR for minute adjustment is connected with said resistors. Movable terminal of the resistor VR is connected with connecting point of the electrode A and the amplifier B and also, output side of the amplifier B is connected with the parallel circuit of the feedback resistor r1 and variable resistor r2 for temperature compensation and the pointer M. The resistance values of the resistors R1-R5 are successively small and these resistors have the resistance values in accordance with the kind of the grain, therefore the resistance value according to the kind of grain is selected by the switch S to indicate the degree of moisture in the pointer M. |
