What could cause contact failure due to oxide film during microload switching?

ID: FAQE10082E



The relay may generate an oxide film at the contact point during repeated load switching. However, microload switching cannot break the film by a cleaning effect, which leads to poor contact.


As a guideline to destroy the oxide film, a load of 48 V or more and 100 mA or more has a cleaning effect.


  • For microload switching, it is recommended to use a plastic-sealed relay that is not susceptible to the operating environment.
  • Since gold (Au) is not susceptible to oxidation, select a relay that uses gold alloy contacts suitable for microloads.

For more information, fefer to The SOLUTIONS [General-purpose Relay Edition]: case 09 Contact Failure by Carbons.

Quick tips

  • Select a relay with a contact structure suitable for microload switching.
    Ag alloy < Ag < Au-plated (clad) < Au-plated (clad) twin crossbar structure
  • Select a relay less susceptible to ambient environments.
    Flux resistant < Plastic sealed

Relay models: G6J-2P(F)-Y, G6K-2P(F/G), G6S-2(F/G)

Product category Relays Signal Relays
Classification Trouble shootings
Related keywords
  • Signal relay
  • Microload switching
  • Oxide film
  • Cleaning effect
  • Plastic-sealed relay
  • Gold alloy contact

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