About Ohio Semitronics, Inc.

Ohio Semitronics, Inc. develops and delivers power measurement technologies, transducers, and current sensors, from its plant in Hilliard, Ohio. OSI’s range of measurement technologies perform in a variety of demanding environments such as Petroleum and Petrochemical, Electric Utility, Solar and Wind, Test and Measurement, Automation and Control, and Naval Surface and Subsurface applications.

OSI offers a range of accuracies and linearity specifications to match both the technical and economic needs of their customers. Each accuracy and linearity specification can be certified under NIST and ISO 17025. Accuracy requires consistency, therefore, OSI remains ISO 9001:2015 certified since 2018.

Ohio Semitronics, Inc was founded in 1964 by Dr. W. E. Bulman, a pioneer in the then-emerging field of solid-state physics. Dr. Bulman made OSI the first company in the US to market and develop Hall Effect devices.  Because of Dr. Bulman and OSI’s President Emeritus John Redmyer, OSI has technological roots in both Battelle Institute and Bell Labs.

OSI’s initial products were transducers based on the Hall Effect measurement principles Dr. Bulman outlined in 1952. Since this time, OSI has rapidly developed and evolved a number of accurate electrical and electromagnetic measurement technologies and has successfully defined over 13,000 products. OSI's 13,000+ product line has grown to include voltage transducers, watt transducers, and multifunction meters.

Ohio Semitronics, Inc products are driven by customers’ expanding needs. As customers innovate, OSI develops, or in some cases, creates a measurement solution to meet customer needs. This breadth of offering is enabled by a customer’s ready access to a team of application specialists who work to understand customer applications, and then select or create the proper solution.


Current Measurement
  • AC, DC, Variable Frequency
  • Milliamps to >100,000A
  • DC to 100kHz Bandwidth
  • -55° to +125° C Operating Range
  • Microsecond Response
  • AC or DC Instrument Power
Voltage Measurement
  • AC, DC, Variable Frequency
  • Millivolts to 7.5kV
  • DC to 10kHz Bandwidth
  • -20° to +80° C Operating Range
  • Microsecond Response
  • AC or DC Instrument Power
Frequency Monitoring
  • AC and Variable Frequency
  • 0-1,000Hz Frequency Monitoring
  • Millisecond Response
  • -20° to +80° C Operating Temperature
  • Self-Powered or AC Instrument Power
  • EMI Protected
Power Measurement
  • Power (Watts)
  • Energy (KWH)
  • Reactive Power (VAR)
  • Reactive Energy
  • Current
  • Voltage
  • Frequency
  • Power Factor
  • Volt Amps
  • Panel Mount
  • Remote Displays
  • Limit Alarms
  • Serial Communication
  • Analog Outputs
  • True RMS Readings
  • Monitoring Distorted
    Waveforms up to the
    40th Harmonic