- Legal name
- Würth Elektronik eiSos GmbH & Co. KG
- Founded
- 1976The electronics business. The Würth Group it belongs to dates from 1945.
- Headquarters
- Waldenburg, Baden-Württemberg, Germany
- Group
- Part of the Würth Group
- Capability layer
- Wireless power
- Product areas
- EMC components and filters · Inductors · Capacitors · Transformers · Power modules · Connectors · Wireless power transfer coils
- Production sites
- Germany, Czech Republic, Bulgaria, United States, Mexico, China, Taiwan, ChinaAs published by the company.
- Website
- we-online.com
- Directory status
- Listed company — compiled from public information. Not a member.
What the company does
Würth Elektronik eiSos manufactures electronic and electromechanical components. It was founded in 1976, is headquartered in Waldenburg in Baden-Württemberg, and is part of the Würth Group — a distinction worth keeping, because the group's own history starts in 1945 and the electronics business does not.
The portfolio covers EMC components and filters, inductors, capacitors, transformers, power modules, connectors and wireless power transfer coils, with production sites in Europe, the Americas and Asia. Alongside the coils themselves the company publishes reference designs and application notes for wireless power, which is a meaningful part of what a component supplier contributes at this layer.
Where it sits in the chain
Wireless power is the third layer of the industry map. It determines coil geometry, coupling, foreign object detection and thermal derating — in other words, how much energy arrives at the device and how much is lost on the way.
This layer has an unusual property: the component supplier often knows more about how the part behaves in a system than the integrator does at the point of choosing it. Coils are selected against a reference design, and the reference design is frequently the supplier's. That makes the quality of the supplier's documentation a real part of the product's performance, not a marketing extra.
What to check when sourcing at this layer
Whether the coil was characterised in a system or on a bench. A coil measured on its own gives inductance and resistance. What a designer needs is behaviour inside an assembly — with the shield, with the spacing, with the actual receiver. Suppliers that publish system-level characterisation remove a large part of the integration risk.
Foreign object detection is a system property. A coil cannot detect a coin or a key on its own; that comes from how the whole design monitors power loss and temperature. It is worth asking which part of the design is responsible, because the answer is usually "firmware someone wrote", not "a component someone bought".
Derating curves rather than a headline wattage. A coil rated at a peak power figure will not hold that figure indefinitely in a closed enclosure. The derating curve — power against temperature, or power against duty cycle — is the document that describes what the part actually does.
Qi2 explained and the glossary entry on foreign object detection cover the surrounding detail.
Note on this entry
This entry was compiled by the alliance from the public sources listed below. It was not supplied, reviewed or approved by the company. Würth Elektronik is not a member of the alliance, and listing is not an endorsement, a recommendation or an approval of any product.
The alliance has not tested any product from this company and does not know which coils appear in which products. Where that matters, ask the supplier for the part number and check it against the maker's own datasheet.
Sources
This entry was compiled by the alliance from the public sources listed below. It was not supplied, reviewed or approved by the company.
- Würth Elektronik — corporate site, including the Waldenburg headquarters and the component portfolio (accessed October 2026)
- Würth Elektronik group profile, stating the 1976 founding and the production site list (accessed October 2026)