固态继电器的分类与应用电路（Classification and application circuit of solid state relay）.docVIP

固态继电器的分类与应用电路（Classification and application circuit of solid state relay） Classification and application circuit of solid state relay Relay, circuit, classification, application 1. solid state relay (Solid State Relays, abbreviated SSR) is a contactless electronic switch, composed of discrete components, fixed film resistor networks and chip, using hybrid technology to realize assembly control loop (input circuit) and load circuit (output circuit) electrical isolation and signal coupling, by solid-state devices to achieve load. Switch function, no internal moving parts. Although there are a large number of solid state relays on the market, their operating principles are essentially similar. It is mainly composed of three parts: input (control) circuit, drive circuit and output (load) circuit. The input circuit of the SSR is to provide a loop for the input control signal, which makes it the trigger source of the ssr. The input circuit of solid state relay is mostly DC input, and the other is AC input. The DC input circuit is divided into resistive input and constant current input. The input control current of the resistive input circuit varies linearly with the input voltage. Constant current input circuit, when the input voltage reaches a certain value, the current will no longer increase with the increase of voltage, this relay can be applied to a wide range of input voltage. The driving circuit of the solid state relay can include three parts: isolated coupling circuit, functional circuit and trigger circuit. Isolated coupling circuits are currently using two types of circuit: optocoupler and high frequency transformer. Commonly used optocoupler, light triode, light bidirectional thyristor, light diode array (photovoltaic volts) and so on. The coupling of high frequency transformer is to form a self-excited oscillation of about 10MHz under a certain input voltage. The high frequency signal is transmitted to the transformer secondary through the transformer core.