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LEM LogoLEM USA, Inc., known as LEM (Liaisons Electroniques et Mecaniques), stands as an international leader in current and voltage sensing technologies. Specializing in Hall effect transducers, LEM offers cost-effective, isolated solutions for measuring current and voltage in a wide array of power electronics applications. These applications span across industries such as Uninterruptible Power Supplies, Switch-Mode Power Supplies, converters, motor drives, and battery monitoring for the industrial, automotive, and railroad markets. LEM's transducers are designed to measure DC, AC, and complex waveform signals, providing galvanic isolation. Manufactured to stringent standards, these products are produced in world-class facilities located in America, Europe, and Japan.

As a market leader, LEM delivers innovative, high-quality solutions for measuring electrical parameters. The company's core products - current and voltage transducers - find applications in drives, welding, renewable energies, power supplies, traction, high precision, conventional, and green vehicles. LEM's strategy is centered on leveraging its core strengths while exploring opportunities in both existing and emerging markets with new applications. Production facilities are strategically located in Beijing (China), Geneva (Switzerland), Sofia (Bulgaria), and Machida (Japan). With regional sales offices situated close to customer locations, LEM provides seamless service globally.

Listed on the SIX Swiss Exchange since 1986 with the ticker symbol LEHN, LEM is a mid-size, global entity with approximately 1,200 employees worldwide and reported sales of CHF 245.6 million in the financial year 2013/14. The company's core values, including customer focus, integrity, teamwork, commitment, excellence, and innovation, are central to its operations and growth.

Featured Products 

GO Series Coreless Integrated Primary Current Transducer with Dual OCD

LEM’s GO series

introduce LEM’s GO series, a coreless integrated primary current transducer with dual over current detection output.

The GO Series Coreless Integrated Primary Current Transducer with Dual OCD is a cutting-edge solution offered by LEM. This innovative transducer combines a coreless design for improved accuracy and reliability with Dual OCD (Offset Current Detection) technology. The coreless design eliminates magnetic saturation effects, ensuring precise measurements even in demanding environments. Dual OCD technology enhances safety and performance by detecting and signaling any offset in the current measurement. This compact and efficient transducer is ideal for a wide range of applications, providing accurate and reliable current sensing in industrial, automotive, and railway systems.


HOYS/HOYL Product Family
Features, applications, and the open loop ASIC of LEM’s HOYS and HOYL open-loop current transducer families.

The HOYS/HOYL Product Family by LEM is a comprehensive range of Hall effect current sensors designed for high accuracy and performance. These sensors offer precise measurement of DC, AC, and pulse currents, making them ideal for applications in industrial, automotive, and renewable energy sectors. The HOYS series features open-loop sensors with high isolation voltage, while the HOYL series offers closed-loop sensors for enhanced accuracy and linearity. With various package options and output configurations, the HOYS/HOYL Product Family provides versatile solutions for current sensing needs, ensuring reliable operation in a wide range of electrical systems.

Digital Transducers with Sigma-Delta Output

Digital Transducers with Sigma-Delta Output
LEM's ASIC with on-board second-order Sigma-Delta modulator provides a digital output to open-loop transducers.

LDSR Leakage Current Measurement

LDSR Leakage Current Measurement for Safety
Introduce LEM's LDSR leakage current measurement for safety.


LXS/LXSR/LES/LESR/LKSR/LPSR Closed-Loop Series with Fluxgate Performance
Introduce LEMs Closed-Loop Series with Fluxgate Performance.

Smart-Grid Focused ART Series of Rogowski Coils

Smart-Grid Focused ART Series of Rogowski Coils
Features, applications, and key points of the ART series.

The Smart-Grid Focused ART Series of Rogowski Coils by LEM is designed to meet the specific needs of smart grid applications. These Rogowski coils offer flexible and accurate current measurement for power quality monitoring, energy management, and grid optimization. The ART Series features advanced Rogowski coil technology, providing high accuracy even in the presence of harmonics and distorted waveforms. With a wide dynamic range and fast response time, these coils are ideal for smart grid systems requiring precise current measurement. The ART Series Rogowski Coils from LEM are an integral part of advanced solutions for modern power grids, ensuring efficient and reliable operation.

LEM Components Catalog