As one of the four basic structural components of the automobile connector, the main function of the contact is to build a communication bridge between the blocked or isolated circuits in the circuit, so as to make the current flow and realize the predetermined function of the circuit. The contact is the core part of the automobile connector to complete the electrical connection function. Generally, the contact pair is composed of male contact and female contact, and the electrical connection is completed through the insertion of female and male contact.

The male contact is a rigid part, and its shape is cylindrical (round pin), square cylinder (square pin) or flat (insert).

Male contacts are generally made of brass and phosphor bronze. The female contact, namely the socket, is the key part of the contact pair. It relies on the elastic structure to produce elastic force when it is inserted with the pin to form close contact with the male contact and complete the connection.

There are many types of jacks, including cylindrical (slotted, necked), tuning fork, cantilever (longitudinally slotted), folded (longitudinally slotted, 9-shaped), box (square jack) and hyperboloid spring jacks.