| 摘要 |
PROBLEM TO BE SOLVED: To reduce the cost of a dish washer-drier, to improve the latitude of designing and to improve the reliability of operation in manufacture by reducing the number of components and its occupancy space in the dish washer- drier controlling a water feeding valve or a draining device by detecting a water level. SOLUTION: A pair of electrodes 12, 13 is arranged at a prescribed distance from the bottom surface of a washing tub 11. An AC signal source 16 and a first rectification smoothing circuit 17 are connected to the first coil 14a of a magnetic combining circuit 14 via a resistor 15. A second rectification smoothing circuit 18 is connected to the second coil 14b of the circuit 14. The output of the circuit 18 is set to be a power source, the electrodes 12, 13 are set to be as input terminals and current flowing through a resistor between these is set to be a signal source current. Then the current is amplified to make a power source current flow through a current amplifier circuit 19. Thus, the output voltage of the circuit 17 controls the operation of a water feeding valve 21 feeding water to the tub 11 by the output of a judging circuit 20 varying a level with a fixed value as a boundary.
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