Hybrid relay

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A hybrid relay consists of two different switches with different properties. It consists of a semiconductor relay and an electromechanical relay , which are housed together in one housing. It has a common control input for both switching devices, which controls them with a delay via an internal logic according to the task.

Structure and control

In a hybrid relay, a semiconductor switch and an electromechanical relay are installed in parallel and connected to an electronic control circuit. When switching on, the semiconductor element is activated first and after a short delay, when the current flow has stabilized, the electromechanical relay is closed. The semiconductor switch is then deactivated and the mechanical relay takes over the entire current. Switching off takes place in the reverse order: The semiconductor switch is activated, then the mechanical relay is opened. Shortly afterwards, the semiconductor switch is also deactivated (possibly in the zero crossing of the current) and the hybrid relay is switched off.


The hybrid relay combines some of the advantages of solid-state relays and electromechanical relays:

  • By bridging the semiconductor component in stable operation, there is no heat loss , the contact resistance is lower and no (or smaller) heat sinks are required.
  • Like the electromechanical relay, the hybrid relay can be heavily overloaded for a short time.
  • The switching arc that occurs with purely electromechanical relays is greatly reduced. This increases the service life of the electrical contacts significantly and the service life of the hybrid relay can be extended up to more than a thousand times.
  • The load can be switched off in the zero crossing and thus generates less interference .


Hybrid relays are used where high reliability or low levels of interference are required. They are also used where pure solid-state relays cannot be used for reasons of space or for thermal reasons, but a pure electromechanical version is out of the question.