The electrical connector is electrically connected to the electrical circuit element. Therefore the electrical parameters are selected connector should first consider the question.
Rated voltage
Rated voltage called working voltage, it mainly depends on even the machine used by the insulating materials, contact between the pair of spaced size. Some element or device below its rated voltage, may not perform its function. Connector rated voltage in fact should be interpreted as the manufacturer recommends a maximum working voltage. In principle, the connector in the lower than the rated voltage can work normally. The author tends to according to the connector of the pressure ( dielectric strength ) index, according to the use environment, security requirements to a reasonable selection of rated voltage. That is to say, the same pressure index, according to the different use of the environment and safety requirements, can be applied to different maximum working voltage. This is consistent with the objective situation. Rated current rated current and working current. With the rated voltage, rated current in lower case, connectors generally can work normally. The connector design process, is based on the thermal connector designed to meet the requirements of the rated current, because is in contact with the current flows, due to the presence of the conductor resistance and contact resistance, contact will heat. When the heating exceeds a certain limit, will destroy the connector insulation and forming a contact on the surface coating of softening, caused by a fault. Therefore, to limit the rated current, in fact limit connector internal temperature rise not to exceed the specified value design. Choose to pay attention to the question is: for the connector, the rated current must be derated to use. In the current situation should be attached great importance, such as diameter of 3.5mm exposure on general provisions, the rated current of 50A, but in 5 core to derating 33%, namely every core current rating of only 38A, core number, derating the larger amplitude. Derating amplitude can refer to table 1
Contact resistance
Contact resistance refers to the two contact conductor in contact resistance. In the selection of should pay attention to two issues, first, the connector contact resistance index is in fact contact resistance, which comprises a contact resistance and contact resistance of a conductor. Usually the conductor resistance is small, so the contact resistance in many technical specification known as the contact resistance. In second, connecting the small signal circuit, attention should be paid to give contact resistance index is under what conditions test, because the contact surface will annex the oxide layer, oil or other contaminants, the two contact surface will produce a film resistor. In the film thickness increases, the resistance increases quickly, is a film become poor conductor. However, the film in high contact pressure occurs under the mechanical breakdown, or in a high voltage, high current occurs under the electrical breakdown. For some small size connector design for contact pressure is quite small, the use of occasions only mA and mV film resistance, not easy to be broken down, may influence the transmission of electrical signal. In GB5095" in the electric equipment with mechanical and electrical components basic testing procedures and measuring methods." in the contact resistance test method of contact resistance was executed" --" provisions, in order to prevent the contact insulating film is breakdown, test circuit open-circuit EMF DC or AC peak value should be less than 20mV, DC or AC current test should be not more than 100mA. In fact this is a low level contact resistance test method, therefore, the requirements of the selection, as selected by the low level contact resistance indexes of connector.