The internal mechanism of the intermediate relay

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### Coil - **Structure**: Generally, it is made by winding copper wire around a magnetic core and is a key component for generating an electromagnetic field. When an electric current passes through the coil, a magnetic field will be generated around it, thus driving the other components of the relay to work.

- **Function**: Whether it is energized or not determines the working state of the relay. It is the core of realizing electromagnetic conversion and provides a power source for the operation of the entire relay.

### Iron Core - **Structure**: It includes a fixed iron core and a movable iron core. The fixed iron core is used to support the coil and serves as part of the magnetic circuit; the movable iron core is attracted by magnetic force when the coil is energized, thus driving the action of the contacts.

- **Function**: Together with the coil, it forms an electromagnet, enhances the magnetic field strength, enabling the relay to generate sufficient suction to drive the closing and opening of the contacts.

### Contacts - **Structure**: They are switches made of metal materials and are used for controlling the on-off of circuits. They usually include normally open contacts and normally closed contacts, and their quantity and types are determined according to the model and application of the relay.

- **Function**: When the relay operates, the normally open contacts close and the normally closed contacts open, realizing the control of external circuits and the transmission of signals; when the relay resets, the contact states return to their original states.

### Spring - **Structure**: Generally, it is made of materials with good elasticity and corrosion resistance, such as stainless steel. - **Function**: It is used to reset the movable iron core when the coil is de-energized, thus driving the contacts to return to their initial states. The elasticity of the spring directly affects the reset speed and reliability of the contacts.

Housing - **Structure**: It is usually made of plastic or metal and has certain strength and insulation properties.

- **Function**: It protects the internal components of the relay from the influence of the external environment, such as dust, moisture, mechanical collisions, etc., and also plays an insulating role to prevent short circuits and other failures between the internal circuit and external devices.

Terminal Blocks - **Structure**: They are the interfaces for connecting the relay to external circuits and usually include coil terminal blocks and contact terminal blocks. Their materials have good electrical conductivity and corrosion resistance.

- **Function**: They facilitate the connection of the relay to the circuit, ensuring that the electric current can flow into the coil smoothly and that the contacts can be correctly connected to external loads or control circuits.