The BH Series

The BH Series, available from AI-Tek, are Bi-directional, zero velocity sensors are self-calibrating to the specific customer application and provide two independent frequency outputs and a direction signal output to indicate change in direction of the sensed, ferrous target.

The BH Series bi-directional sensor can also be referred to as a dual-channel sensor since it utilizes two Hall effect sensing elements that physically offset from each other. Each element generates a single channel of target information, identical in frequency and polarity, but offset in the time domain (phase shifted). 

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AI Tek BH Series

How the BH Series Works

Special circuits inside the sensor are designed to calibrate each channel to its application target, then analyze these two channels of information for a phase lead / lag condition. The direction output will then provide a logic 1 level for clockwise or a logic 0 for counterclockwise rotation, assuming proper sensor orientation.

For applications with cable runs that exceed 500 feet, you will need to use a Digital Signal Distance Amplifier (DSDA).

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Key Features of the BH Series

Suitable for 32 diametral pitch or coarser gear (target), the standard catalog sensors are easily applied to your various sensing needs. If you have a unique, special requirement that cannot be met with any of the standard options, we will gladly review your specs and work with you on a special sensor design.

It is the customer's responsibility to determine whether the product is proper for customer's use and application.


  • High temperature range of -40°C to +125°C
  • Supply Tracking or TTL Compatible output options
  • Power on calibration
  • Requires special alignment
  • Controlled duty cycle
  • Fine pitch performance
  • Increased air gaps
  • Wide range of supply voltage in single design of 10 - 28 Vdc
  • Special circuitry provides high level of EMI hardness
  • Reverse voltage protection, up to -30 Vdc, to prevent damage if miswired
  • Rugged sensors designed to meet the toughest Navy ship-board standards to European Railroad Applications

More Active Speed Sensors from AI-Tek

In addition to the BH Series, AI-Tek Instruments also offers other active (hall effect) speed sensor products, including the DH and RH Series. 

AI-Tek Resources

Not sure which speed sensor makes sense for your application? Use the AI-Tek Product Finder to find out.


Use the AI-Tek calculator to ensure that your sensor selection will produce enough output for your application.



Get In Touch

Are you ready to make a purchase or looking for more information on a specific product? Get in touch with someone from AI-Tek or find a distributor near you. If you have a unique, special requirement that cannot be met with any of the standard options, contact us to learn more about custom sensor options.