ECE-直流机接触器-价格行情

SSR uses photosensitive MOSFET devices with LEDs to drive the device.Solid state relay (SSR): Light from the packaged LED activates the photosensitive MOSFET and allows current to flow through it.There will still be significant differences between DC machine contactors and solid-state relays.

SSR is a faster alternative to electromechanical relays, as their switching time depends on the time required to turn on and off the LED - approximately 1 ms and 0.5 ms, respectively. Due to the absence of mechanical components, their expected lifespan is longer than that of electromechanical or reed relays.

FET switches are commonly used in multiplexer configurations to achieve high-speed and low-voltage applications.

SSR is very useful for high-voltage applications because LED drivers do provide an electrical isolation barrier between the control circuit and MOSFET. However, due to the switching operation of MOSFET, there is no electrical isolation layer between its contacts. When there is no gate driver on the MOSFET, the drain source channel on the MOSFET has a high resistance, providing a disconnect between the contacts.

Because the connection is made through transistors rather than physical metals in electromechanical and reed relays, the contact resistance of SSRs is higher. Although technological advancements continue to improve the contact resistance of SSRs, it is still common to find resistance of 100 Ohm or higher in production today.

SSR is not as powerful as electromechanical relays. Similar to reed relays, they are highly susceptible to surge currents and damage when used at signal levels higher than their rated values. Although there are no metal contacts that need to be soldered, MOSFET damage can render the relay unusable SSR is common in matrices and multiplexers.