(3) Number of contact pairs and pinholes. First, the number of contact pairs can be selected according to the needs of the circuit, taking into account the size of the connector and the total separation force. The number of contact pairs is large, of course, its volume is large, and the total separation force is relatively large. In some cases with high reliability requirements and allowable volume, two pairs of contact pairs can be connected in parallel to improve the reliability of the connection. In the plug and socket of a connector, pins (male contacts) and sockets (female contacts) are usually interchangeably assembled. In actual use, you can choose according to the live condition of the plug and the socket. If the socket needs to be charged normally, you can choose a socket with a socket, because the live contact piece with the socket socket is buried in the insulator, and the human body is not easy to touch the live contact piece, which is relatively safe.