Correctly selecting the contact material can improve the reliability and life of relay IRF520NPBF. Different relays are different due to the different nature and disconnection capacity of the contact load, and the types and degrees of wear of the contacts are also different; these factors must be taken into account when the design uses contacts and reed materials. The selected contacts and reed materials should meet the following basic requirements:

　　① It has good conductivity and thermal conductivity.

　　② The contact and plating material should be resistant to arcs or electrical spark wear and mechanical wear, and have a certain hardness and anti -adhesion performance.

　　③ The reed material should have good elasticity.

　　2) Requirements for the design and size design of the contact contact:

　　① For small and small loads such as micro -micro, ultra -small, the contacts should be in contact with point contact. PCB copies to increase the pressure on the contact site and destroy pollutants on the surface of the contact surface. For large load relay, the contact should be in the form of face contact to increase the heat dissipation area and slow the contact electrode wear.

　　② In the form of contact combination, the assembly form should be avoided as much as possible, reducing the unreliable factors brought by assembly, and riveting with reliable melting welding.

　　③ Use the contacts of different materials for pairing to improve the anti -arc and abrasion capacity of the contact.

　　④ The design quality of the reeds should be small, and the size should not be too long. If the material with high elastic modulus is used, the circuit board cloning reduces the proportion of the material or increases the rigidity of the reed to make its resonance frequency higher than the given environmental frequency indicator. So as to ensure the environmental adaptability of impact and vibration.