What is the difference between single contact, twin contacts and crossbar twin contacts in the contact mechanism for relays?

ID: FAQE10001E



Contact configurations are classified into three types according to the reliability level: Single contact, Twin contact and Cross-bar Twin contact. Refer to Explanation.


The following table shows typical contacts of our relays.

Typical contacts of relays
  • We have a double (or twin) break contacts type relay in our single contact relays. Double break contacts are suitable for opening and closing large-capacity loads that require breaking capability due to the large gap between the same polarity contacts.
  • Crossbar single contact has the advantage of providing good contact matching even with slight contact misalignment, and is used for relatively small current capacities.
  • The crossbar twin contacts have two contact points and have the advantage of a crossbar shape, making it suitable for opening and closing microloads.

For more information, see Relay Basics:Technoligy.

Quick tips

Select a signal relay (communication) for microload switching.

Related document

Product category Relays Signal Relays Power Relays
Classification Selection, Characteristics
Related keywords
  • Signal Relays
  • Power Relays
  • Single Contact
  • Twin Contacts
  • Crossbar Twin Contacts

Related Questions

Which relays are suitable for microloads?
When operating with a microload, use the applicable load condition of the failure rate P level (reference value) as a guide.
What is the failure rate P level on the datasheet of the mechanical relay?
The P level (reference value) indicates that a failure is expected to occur once in every 10 million cycles in the event of a microload as specified in JIS C 5003.
What does contact reliability mean in relation to microloads?
Contact resistance may be a problem when opening and closing microloads, which increases the possibility of low contact reliability. If a high contact resistance value is accidentally generated, it may be recovered by the subsequent operation.
In addition, contact resistance may increase due to generation of contact coating.
Whether or not the contact resistance value is considered a failure depends on whether or not a problem occurs in the circuit.
For this reason, the failure criteria for the contact resistance of relays are specified only in the initial value, and the failure rate is expressed using the P level (reference value) as a guideline for the minimum applied load.
Note that some relay contacts are suitable for opening and closing microloads, while others are not.

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