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There's no contact like contact.


A switching relay provides switching of the output load. The parameters of the output relay usually also provide the technical parameters of the output of the entire device, which generally differ with each producer of these devices.

The main factors observed for the output relay are:

  • the number and type of output contacts
  • the maximum switched current, voltage – minimum switched DC voltage and current
  • type of switched load (resistive, inductive…) and the electrical/mechanical service life of contacts

In smaller measure, contactless elements (triacs, transistors) are used at the output.

The category of use (incorporation) of the given relay determines the material of output contacts. The basic types of materials used for producing contacts of power relays are:

  • AgCd – appropriate for switching ohmic loads. Due to harmfulness of the element Cd, there is a current trend of avoiding its use.
  • AgNi – designed for switching resistive loads, it switches well and transmits (does not oxidize) low currents/voltage, not designed for surges and loads with a portion of an inductive component.
  • AgSn or AgSnO – appropriate for switching loads with a portion of an inductive component, it poorly switches low currents/voltage, it is more resistant to surges, appropriate for switching DC voltage, less appropriate for switching loads of an ohmic nature.
  • Wf (wolfram) – special contact designed for switching surges, where there is a portion of an inductive component.
  • admixture of gold (AgNi/Au) – used to "improve" contacts for low currents/voltage, preventing oxidization.

Our company uses relay contacts AgNi and AgSnO

Contact AgNi 
Relays with AgNi contacts are fitted to most industrial devices (mainly time relays), where they are expected to be deployed in industrial switchboards and switch the power section by means of additional contactors. Therefore, the contact of this relay is not directly exposed to high or problematic loads such as switching motors, drives, lighting, etc. The advantage of AgNi is found in switching control logic (5V) and low voltage (24V) for various PLC devices, control systems and control circuits.
All these loads should be in usage category AC-1.

Contact AgSnO
Relays with AgSnO contacts have proven to be more advantageous, and we have been using them for almost 20 years. This need arose with the introduction of devices for home installations determined mainly for switching the lighting. Indeed, the term "lighting" must be considered not only lamps, but also various types of other light sources such as fluorescent lamps, compact fluorescent lamps, fluorescent lamps with electronic and classic ballast, LED light sources, etc.

Products with AgSnO contacts are supplied by such renowned suppliers as Tyco Electronics. The number of switching operations (service life) of the relay is several times higher than that of Chinese relays. 

We do not introduce the price difference between the AgSnO contact and AgNi contact (AgSnO contacts are somewhat more expensive) into the price of our products! 

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