Home > Electro-Mechanical Components > LEM USA


LEM ElectronicsLEM Electronics - LEM (Liaisons Electroniques et Mecaniques) is an international group and the world leader in current and voltage sensing. LEM manufactures Hall effect, cost effective, isolated current and voltage transducers used in a wide range of power electronics applications such as: Uninterruptible Power Supplies, Switch-Mode Power Supplies, converters, motor drives, battery monitoring, for the industrial, automotive and railroad markets.

The current and voltage transducers measure DC, AC and complex waveform signals and provide galvanic isolation. They are all designed and manufactured according to the most demanding standards, in world class manufacturing facilities in America, Europe and Japan.

LEM - Mechanical Components

LEM is the market leader in providing innovative and high quality solutions for measuring electrical parameters. Its core products - current and voltage transducers - are used in a broad range of applications in drives & welding, renewable energies & power supplies, traction, high precision, conventional and green cars businesses. LEM’s strategy is to exploit the intrinsic strengths of its core business, and to develop opportunities in existing and new markets with new applications. It has production plants in Beijing (China), Geneva (Switzerland), Sofia (Bulgaria) and Tokyo (Japan). With regional sales offices near its customers’ locations, the company is able to offer a seamless service around the globe. LEM has been listed on the SIX Swiss Exchange since 1986; the company’s ticker symbol is LEHN.

LEM connectors LEM is a well-known manufacturer of current transducers and sensors. LEM is a global company specializing in the design and production of components for measuring electrical parameters, particularly in the field of current and voltage measurement. LEM's current transducers are widely used in various industrial applications for monitoring and control purposes.

LEM offers a diverse range of current transducers designed to measure AC (alternating current) or DC (direct current) in various electrical systems. These transducers are capable of accurately converting current signals into proportional voltage or current signals for monitoring and control purposes.


GO Series Coreless Integrated Primary Current Transducer

GO Series Coreless Integrated Primary Current Transducer with Dual OCD

LEMS's GO series transducer with dual overcurrent detection features excellent accuracy, speed, and external field immunity

LDSR Series Current Transducers

LDSR Series Current Transducers

LEM's LDSR series current transducers are PCB mounted and designed for photovoltaic (PV) applications.

ATO Series Split Core Current Transformers

ATO Series Split Core Current Transformers

LEM's ATO series is a split core current transformer for the electronic measurement of AC waveform current.

ART Series Split Core Rogowski Coils

ART Series Split Core Rogowski Coils

LEM's ART series provides ease of use with its flexible clip-around application for a wide range of cable diameters. The patented Perfect Loop Technology dramatically reduces both the error due to the position

Company History

2013 LEM expands European manufacturing with new facility in Bulgaria of 4,500 square meters, and creates 50 new jobs over there.
2012 40th Anniversary of LEM Group.
2011 Record of sales with over CHF 296 million of total sales.

LEM acquires the Danish company Danfysik ACP (Advanced Current Products) A/S, the world’s leading company in the development and manufacturing of highest precision current transducers for three main markets: medical scanners, precision industrial motor controls and test & measurement.

A new facility in Beijing China is opened featuring 10’000 m3 of production and office space. Celebration of the 20 year anniversary of LEM in China.


Launch of a new flagship product: the DV, the first compact DC, Class 1 accurate voltage transducer for the traction market. Total sales of CHF 203 Million.


Launch of 3 flagship products: Minisens - a transducer the size of a chip, Sentinel to monitor standby batteries and Wi-LEM to measure energy consumption and communicate this data via a wireless network. Total sales of CHF 184.5 Million.


LEM is a "pure play" components company providing solutions for current and voltage measurement. Total sales of over CHF 150 million achieved.


Divestment of Instruments business to Danaher Corp and divestment of the CTN real estate as part of the strategy to focus on the core competencies of the company.


Divestment of High Current System business, LEM DynAmp in Columbus/Ohio by a Management Buy-out. New company is named DynAmp, LLC.


Acquisition of the Transducer business of HINODE Electric KK, in Tokyo, Japan.

LEM acquires 65% of the shares of the Paris-based company Universal Technic S.A.


LEM acquires 100% of the Belgian company Electronics Instruments International SA (EII).


Joint Venture with the Japanese company NANA Electronics K.K., and foundation of the common NANALEM K.K.

First customized ASIC-based closed-loop transducers for the automobile industry.


Joint Venture with the Belgian company ACT´L SA and foundation of ACTLEM.

LEM divests its Recorder business.


Acquisition of Dr. Werner Mühlegger F&E GmbH and Integration in LEM NORMA GmbH.

Conversion of the Power Semiconductor Test Instruments business unit into the independent LEMSYS company.


25th Anniversary of LEM Group. Reaching over CHF 100 million of total sales.

Foundation of Centre de Technologies Nouvelles (CTN) SA with capital of CHF 50 million.

Foundation of LEM Nederland BV.


Re-organization of LEM leading to two Business Areas (BA): Components, Instruments and
two Business Units (BU): Test Systems, High Current Systems.


Integration of NGI NORMA GOERZ Instruments in Wiener Neudorf/Austria.


Integration of ELMES-Staub AG/Switzerland.

Total sales of CHF 50 million.


Take-over of the high-current measurement activity from the American manufacturer almar, to the LEM DynAmp Columbus/Ohio.


Creation of the Russian joint venture company TVELEM.

City of Geneva Award for industry.


Increase of the share capital to MCHF 30. Purchase of 80% British company HEME International Ltd. (HEME = Hall Effect Measurement Equipment). Entry into the instruments market.

Formation of the Chinese joint venture company Beijing LEM.


Creation of the Japanese subsidiary Nippon LEM KK.

Total sales of CHF 20 million.


Formation of the North American subsidiary LEM USA Inc, of the German subsidiary LEM Deutschland GmbH and of the Swedish subsidiary LEM Scandinavian AB.


City of Geneva Award for Industrial Merit.


Start of the building of the CTN (New Technology Centre). Introduction of LEM on the Geneva stock-exchange.


Creation of LEM Holding SA with a capital of CHF 6.2 million.


Creation of LEM France SARL.


The first 300 A current transducer is integrated into the concept of the Swiss trolley-buses.


Feb. establishment of Liaisons Electroniques-Mécaniques LEM SA with a capital of 200,000 CHF, 17 shareholders.


LEM products fall broadly into multiple areas of application and are used within general industry, automotive industry, for railway and trackside applications, energy measurement relating to railway on-board applications, energy & automation, battery monitoring, and in Wi-LEM - wireless sub-metering networks that measure energy consumption.

Industry applications

  • Isolated current and voltage measurement with instantaneous current or voltage output. Non contact or with integrated conductor or clip-on current measurement from 0.1 A to 20,000 A.
  • High voltage measurement from 10 V up to 6,400 V.
  • Different technologies used to cover required performances, such as accuracy from some ppm to several percents, or response time, bandwidth.

Railway and trackside applications

  • Isolated current and voltage measurement with instantaneous current or voltage output.
  • Non contact or with integrated bus bar, or clip-on current measurement from 0.1 A to 20 000 A.
  • High voltage measurement from 10 V to 6,400 V.
  • High modularity offered in the various designs for a high level of mounting flexibility. Large options available for the possible secondary connections inspired by the railway market need.
  • High performances reached (accuracy from 0.2% to 2.7%, short response time from few ns to several μs).

Energy measurement for railway on-board applications

  • EM4T II Energy Meter for Traction. Certified for all European networks. It is an independent accounting certified measuring system for single phase energy metering designed for on-board applications.

Energy & Automation

  • LEM integrated transducers combine in a single case the most advanced AC & DC sensing technologies with signal conditioning electronic circuits (RMS or True RMS, threshold detection, etc).
  • They feature a switch or relay type output or an electrically isolated standard signal (0-5VDC, 0-10VDC or 4-20mA) that can be directly handled by any PLC or monitoring device.
  • These products require complex adjustment and calibration operations and benefit from the LEM technology and manufacturing know-how to achieve the highest performance and quality level of the market.

Battery monitoring

  • The Sentinel intelligent transducer measures cell voltage, internal temperature and internal impedance. It also provides cell voltage and temperature data during battery discharge. This data is passed via a proprietary serial comm. Bus (S-bus) to an Overview and Control System (OCS).


  • Wi-LEM is a wireless sub-metering network to measure your energy consumption: Current max, Voltage min, Active Energy, Reactive Energy, Apparent Energy and Frequency.


  • LEM Automotive specializes in developing and manufacturing current transducers for battery management and motor drive applications in cars, busses and trucks. LEM products can contribute to significant energy savings and an environmental friendly world. By controlling the current in energy-intensive applications LEM participates to the global effort to reduce consumption.

LEM is a both a service partner you can trust and your business partner for innovative, responsive and reliable service solutions.

Our service professionals deliver all these qualities and more to customers in various industry sectors around the globe. With services ranging from trouble-shooting to applications advice, we can improve your product development processes.

Service partner

Our goal is to be a business partner that delivers customized service solutions that improve your operations. Our measure of success is the loyalty of our customers year after year, decade after decade.


Reliability depends on the longevity of the product. All our products come with a 5 year warranty. You can count on our expertise to deliver quality and on our commitment to provide you with innovative solutions for your application. Our teams are renowned in the industry for their dedication. You can rely on us to support you if unexpected problems occur.


You have specific needs, expectations and priorities – we respond to these needs and define with you the best possible solutions for your business.

Innovative solutions

LEM is known within industry for its innovative technology and application know-how. We have over 35 years’ of experience measuring current and voltage.

LEM Automotive Brochure

LEM ITC series Current Transducers