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Does a solid state relay need a diode?
What Is a Solid State Relay? A Solid State Relay (SSR) is a relay that does not have a moving contact. In terms of operation, SSRs are not very different from mechanical relays that have moving contacts. SSRs, however, employ semiconductor switching elements, such as thyristors, triacs, diodes, and transistors.
What is the purpose of the flyback diode placed across an inductor?
Freewheel diode or Flyback diodes are basically connected across inductive coils to prevent from voltage spikes in case of power getting turned off to the devices. There will sharp voltage spike when power to inductive load, i.e. coils and other inductors are turned off.
Do You need A flyback diode for a solid state relay?
In any case, there is nothing inductive there, so no inductive kickback to protect against. If the relay is on the same board as whatever is driving it, then no inductive kickback diode is needed. It’s no different than driving any other on-board LED. However, there can be inductance in the circuit from other than the relay.
How does a solid state relay protect itself?
Protecting a solid state relay from voltage spikes generated by the collapsing magnetic field of an inductive load is a fairly straight forward process. The most frequently used method is to simply place a reverse-biased rectifier diode directly across the load as shown in figure 1 below.
Which is the best diode type for flyback diodes?
Those are the preferred diode type for flyback diodes. I work as a technician for the railways and for our DC traction motors we use flyback diodes that could barely handle the forward motor current but their forward surge current is very high and those diodes rarely break. Thanks for contributing an answer to Electrical Engineering Stack Exchange!
How does a coil suppression diode work on a DC relay?
As seen in figure 3 below, the voltage across the coil when the relay is de-energized still has a conductive path through the suppression diode, similar to what is shown in figure 2. However, the magnetic field will not discharge until the reverse voltage reaches the avalanche voltage of the series zener diode.