Most of the cars as long as a engine cover find relay installation box, can be found to relay trace. Automotive lighting, wiper blade, starter, air conditioner, electric seats, electric Windows, anti-lock braking system, suspension control, acoustics are to use the control relay, it is the most widely used car electronic components, one of the world market demand for more than 1 billion years.
control relay has two main parts, one is the control system, the other is a controlled system. Control relay can the control effect, because when it's control system input a signal, such as electricity, magnetic, thermal, optical and physical quantity reaches a certain value, can make be control system (also called the output circuit) controlled quantity by zero mutation to a certain value, or by a certain value mutation to zero, so as to achieve control, protection, transfer and conversion functions such as information. In small current control large current, is the characteristics of the control relay.
auto control relay technical requirements demanding, because it will adapt to the vibration, high temperature, low temperature, moisture and oil, salt, water erosion resistance severe environment for long service life, high reliability, small volume, low cost, and at the same time with electromagnetic compatibility, flame retardancy, response speed and performance. It was really a feast of eat one's cake and have it, eat one's cake and have it grass. As a motor control relay, it must meet these requirements.
to commonly used car light control relay as an example, mainly have three feet, four legs and feet, five types of control relay. Are control headlights, former small lights and instrument lights, turn lights, tail light, brake lights, reverse lights, fog lamps, car lighting play, etc. When the combination switch dial the to the headlight ON file, headlight relay control system (field coil part) will power ON produce a magnetic field, alloy contact immediately closed, control system of the current conduction, so as to control the opening of the headlight. When the combination switch dial the to the headlight switch OFF the power OFF file, the field vanishes, make control alloy contact immediately, separation of the control system of current cut-off, headlight closed.
the auto control relay still with mechanical is given priority to, but have to solid state relay development. Relay is the key to reliability, because once the relay failure, immediately can cause the system components function paralysis, can cause even the whole car could not move. Such as starter relay failure, the car can't electric start, although most starter relay ten dollars a, but not the car is running it inconvenience.