The water level sensor of automatic washing machine is an LC circuit, which forms an LC oscillation circuit together with the circuit in the computer board. The air pressure changes the inductance, thus changing the frequency of the oscillating circuit, and the computer detects the frequency. Judging water level by frequency.
Outer tub of washing machine: there is an air chamber. When the water level changes, the pressure inside the air chamber also changes. This air chamber is connected with the water level sensor through a plastic pipe.
Structure of water level sensor: there are magnetic rings and coils inside to form LC circuit; When the air pressure rises, a diaphragm will be lifted to drive the coil to move upward in the magnetic ring, thus changing the inductance value. This value will be transmitted to the computer board of the washing machine. The computer board judges whether the preset water level is reached according to the numerical value, and controls the water inflow.
Extended data
How to judge the water temperature and washing quality of automatic washing machine?
The intelligent fuzzy control automatic washing machine can also automatically judge the water temperature, water level, clothes quality and clothes dirt, and decide the appropriate amount of detergent and the best washing program. When the number and texture of clothes in the washing bucket are different, the total weight is different. This can be used to judge the quality and quantity of clothes.
The specific method is: after a certain amount of water is injected into the washing tub, the motor runs at a low speed, and after it stabilizes, the power is cut off quickly, and the washing tub drives the motor to continue to rotate under the inertia. At this time, a rectangular pulse sequence is obtained after half-wave rectification and amplification shaping. By analyzing the pulse number and pulse width. You can get the quality and quantity of clothes.
References:
Baidu encyclopedia-automatic washing machine