Application Note #5 – Converting Millivolt Sensor Outputs to 0–5 V Signals Using the Gain Set Resistor
- John Valentini
- 3 days ago
- 2 min read
In the fifth installment of AVSensors’ 10-part application note series, we return to the analog domain and focus on a common challenge when integrating piezoresistive pressure sensors into instrumentation systems: converting a low-level millivolt bridge output into a usable 0–5 V analog signal. While a Wheatstone bridge sensor accurately represents pressure as a differential millivolt signal, many industrial controllers, data acquisition systems, and microcontroller ADCs require a higher level input. This application note outlines practical signal-conditioning techniques using differential amplification to scale the sensor’s output while preserving accuracy and stability.
The application note explains how AVSensors pressure transducers incorporate laser-trimmed gain-set resistors that normalize sensor span variations and simplify amplifier design. When paired with a differential amplifier stage, this resistor precisely programs the gain required to convert the bridge’s millivolt output into a stable 0–5 V analog signal. This architecture is available across several AVSensors product families including the CHT-2, CHT-3, CTO-7, CTO-8, and CHT-SM565x board-mount series, as well as media-isolated MIOF-154, MIOF-85, and MIOF-86 constant-current sensors designed for liquid and harsh-media environments. Because the gain adjustment resistor is trimmed during manufacturing, interchangeable sensors can produce consistent high-level outputs without requiring extensive recalibration in the end system.
By combining a constant-current excited Wheatstone bridge with a differential amplification stage, the circuit provides predictable span amplification while maintaining sensor temperature compensation and offset correction. The result is a straightforward and cost-effective approach to signal conditioning that transforms millivolt bridge outputs into robust 0–5 V measurement signals suitable for industrial control systems, instrumentation interfaces, and embedded measurement platforms.
Coming Next Month: Application Note #6 – Designing 4–20 mA Pressure Transmitters
While a 0–5 V output works well for many embedded systems and data acquisition platforms, industrial environments often require a more robust signaling method. In the sixth installment of this series, AVSensors will explore how millivolt bridge outputs from pressure sensors can be conditioned and converted into the industry-standard 4–20 mA current loop. This approach offers excellent noise immunity, long cable transmission capability, and inherent fault detection—making it a preferred interface in process control, HVAC, and industrial automation systems.
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Ready to experience the next generation of pressure sensing technology? Contact our team today to find the perfect configuration for your application and see why our expanded pressure sensor family leads the industry in performance and innovation.
John Valentini, Business Development AV Sensors (business.development@avsensors.com)
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