The structure of the thermostat steam irons is very simple. The general electric iron is composed of an electric heating plate (bottom plate), a thermostat (thermostat), an internal wiring set, a heat shield, a water tank, a handle, an upper cover, and a temperature knob (temperature switch) , Steam knob (steam switch), water spray button, explosion button (strong steam switch), protective wire cover, power cord and a series of components.

Working principle: Through high temperature and humidity, the ironing effect is formed after heavy pressure. In recent years, PTC elements are used as heating elements, which can save electricity and can automatically adjust the temperature. To avoid the problem of unreliable temperature control quality of thermoregulators made of bimetallic sheets for old products, new types of electric irons such as jet type, spray type, constant temperature type and electrolytic steam type have also appeared in varieties. High power, light weight, automatic temperature adjustment, steam or spray, and the pursuit of beautiful appearance is the development direction of the new generation of electric irons.

Credit goes to the automatic switch made of bimetal. The bimetallic sheet is made by riveting the copper sheet and the iron sheet with the same length and width tightly together. When heated, because the copper sheet expands larger than the iron sheet, the bimetallic sheet bends toward the iron sheet. The higher the temperature, the more pronounced the bending. The picture on the right is a schematic diagram of the structure of the electric iron. At room temperature, the contacts on the ends of the bimetallic strip are in contact with the contacts on the elastic copper strip. When the electric iron head is connected to the power source, the current flows through the copper sheet and bimetal sheet in contact with the heating wire. The heating wire generates heat and transfers the heat to the metal soleplate at the bottom of the iron. People can use the heating soleplate to iron. The clothes are ironed. As the energizing time increases, when the temperature of the bottom plate rises to the set temperature, the bimetallic strip fixed with the bottom plate is heated and bent downward, and the contact on the top of the bimetallic strip separates from the contact on the elastic copper sheet, so The circuit is broken. At this time, the temperature of the bottom plate no longer rises, and it decreases due to the heat dissipation of the bottom plate; the deformation of the bimetallic strip is gradually restored. When the temperature drops to a certain value, the bimetallic strip and the elastic copper sheet are in contact again, and the circuit is connected again , The temperature of the bottom plate began to rise again. In this way, when the temperature is higher than the required temperature, the circuit is disconnected, and when the temperature is lower than the required temperature, the circuit is connected, and the temperature can be kept within a certain range.

So, how to make the electric iron have different temperatures? When you adjust the temperature control knob up, the upper and lower contacts move up accordingly. The bimetal only needs to bend slightly to separate the contacts. Obviously, the temperature of the bottom plate is relatively low at this time, and the bimetal can control the constant temperature of the bottom plate at a lower temperature. When you lower the temperature control knob, the upper and lower contacts move down accordingly, and the bimetal must be bent to a greater degree before the contacts can be separated. Obviously, the temperature of the bottom plate is higher at this time, and the bimetal can control the constant temperature of the bottom plate at a higher temperature. In this way, the requirements of the fabric for different temperatures can be adapted.