(1) The contact is the core part of the terminal connector to complete the electrical connection function. Generally, the contact pair is composed of positive contact and negative contact, and the electrical connection is completed through the insertion of negative and positive contacts. The male contact is a rigid part, and its shape is cylindrical (round pin), square cylindrical (square pin) or flat (insert). Male contacts are generally made of brass and phosphor bronze. The female contact, namely the jack, is the key part of the contact pair. It relies on the elastic structure to produce elastic force due to elastic deformation when inserting with the pin, and forms close contact with the male contact to complete the connection. There are many kinds of jacks, including cylindrical (split slot, necking), tuning fork, cantilever (longitudinal slotting), folding (longitudinal slotting, 9-shape), box (square jack) and hyperboloid linear spring jack

(2) Insulator insulator is also often called base or mounting plate. Its function is to arrange the contacts according to the required position and spacing, and ensure the insulation performance between the contacts and between the contacts and the shell. Good insulation resistance, voltage resistance and easy processing are the basic requirements for selecting insulating materials to be processed into insulators

(3) The shell, also known as the shell, is the outer cover of the terminal connector. It provides mechanical protection for the built-in insulating mounting plate and pin, and provides the alignment when the plug and socket are inserted, so as to fix the connector to the equipment