The principle of automatic power-off electric kettle?
The steam produced by the boiling of the water causes the bimetallic film of the steam sensing element to be deformed. The deformation drives the power switch through the lever principle and the power is switched off.
The temperature of steam emitted by waterAutomatic power-off function is located inside the cup handle (upper, windpipe or the bottom of the cup, this time need a longer the temperature controller) double sheet metal in the form of implementation, and no relay, the thermistor inside, it is a feeling of steam temperature, so the indirect comparison, generally is the breaking point of water after boiling steam temperature to achieve temperature controller. So, if you open the lid and boil the water, it won't turn off automatically.
Automatic temperature control circuitThe pot boil dry pot is a power automatic temperature control circuit in series. The temperature sensor circuit. The boiling point of water is one hundred degrees, when the water is dried after the temperature will exceed one hundred degrees, when the temperature sensor will disconnect the circuit. The temperature sensor is simple bimetal, commonly used in electric iron electric water heater appliances. Many kinds of temperature sensors. And the semiconductor temperature sensor. It has the advantages of simple structure, safe use, good reliability.
Now a lot of hot kettle, and even remote control, when power supply electric kettle plug with automatic water boiling will not, because it is itself a shockproof device, to the needs of different water users the convenience and safety of the electrical environment. The principle of automatic power-off has several aspects:1 according to the principle of thermal expansion and contraction of objectsThermal expansion and contraction is the object in common, but different objects of their thermal expansion and contraction level is not the same. With metal sheet copper made into contact. Because of thermal expansion and contraction of copper sensitive so in the temperature does not reach the set value of the copper, the metal plate is a curved shape, when the contact is closed. In the water is heated to a temperature of the water when the heat conduction to the copper copper thermostat in the above because the heat will play into contact with the off state. When the temperature drop of copper restored to the original state of the contact switch into electrical heating state. Two double gold sheet is a conductor of different substances, changes in temperature due to expansion is not the same degree of the dual metal sheet bending, meet or contact the switch is set, so that the set circuit starts to work. This can be more timely, accurate temperature sensing.
