Bourns Launches Wirewound Resistors and Sensors for Precise Measurement

The effective management of high-power systems, such as battery energy storage systems and industrial power supplies, depends on the accuracy of internal current and temperature measurements. Component instability, particularly drift caused by thermal variation, introduces systematic errors that reduce system efficiency and safety.

Bourns’ new release of the Riedon-branded precision wirewound components, specifically the 1xxPC, SM8, SM10, and SM/1xx series resistors, alongside the RTDW series temperature sensors, focuses on mitigating these stability issues through specialized construction and material selection.

Bourns’ Riedon Precision Wirewound Resistors feature a resistance range up to 6 MΩ and resistance tolerances of ±0.005%. Image used courtesy of Bourns

Precision Wirewound Resistors

Bourns’ new Precision Wirewound Resistors, the 1xxPC, SM8, SM10, SM/1xx series, are built to function as highly stable current shunts in demanding applications like battery management systems and smart energy metering. The key technical feature driving their utility in precise current sensing is the low temperature coefficient of resistance (TCR), which is rated as low as ±2 PPM/°C. This specification signifies minimal resistance change across operating temperature fluctuations, directly translating to consistent current measurement accuracy.

Further bolstering measurement fidelity, the components feature resistance tolerances as tight as ±0.005%. When deploying these resistors for current sensing, this low initial tolerance minimizes the need for system calibration and compensation at the component level.

Structurally, the resistors utilize non-inductive Multi-Pi cores. This construction technique is critical in preventing transient signal distortion by reducing the component’s parasitic inductance. Low-inductance shunts are essential for maintaining the integrity of fast-switching or high-frequency current waveforms often found in power conversion stages. Furthermore, the series offers high reliability, being 100% acceptance tested and traceable to NIST standards, while exhibiting long-term stability of 100 ppm/year. The components are also sealed with flame and moisture-resistant protective encapsulation.

Bourns’ Riedon RTDW series of resistance temperature sensors features a temperature sensing range of 0 °C to 100 °C. Image used courtesy of Bourns

Precision Wirewound Temperature Sensors

In parallel with the ultra-precision resistors, the Riedon Precision Wirewound Temperature Sensors, the RTDW series, provide users with a reliable tool for thermal monitoring. These sensors are engineered to function as resistance temperature detectors (RTDs), where the material’s large, predictable resistance change with temperature is the primary sensing mechanism.

The RTDW sensors achieve this via material selection that permits a wide TCR range, reaching up to ±6000 PPM/°C. This high TCR allows for a substantial change in resistance across the specified 0 °C to 100 °C general use temperature range, providing robust signal output.

Key design elements focus on mechanical and thermal resilience. The sensors feature all-welded construction for enhanced durability against mechanical shock and thermal cycling, and they also incorporate flame- and moisture-resistant protective encapsulation. They are manufactured with a resistance tolerance down to ±1%.

Bourns’ new Riedon precision wirewound components are suitable for a wide range of applications, including in process control systems, high-frequency circuit designs, and smart meters.  Image used courtesy of Bourns

Precise Current and Temperature Measurement

Bourns’ introduction of Precision Wirewound Resistors and Temperature Sensors provides users with components designed for measurement tasks demanding extreme stability and low error. The combination of ±0.005% tolerance and ±2 PPM/°C TCR in the resistor series specifically addresses the challenge of current sensing in applications where small errors can lead to significant inefficiencies or system failures. The RTDW sensors offer high-TCR thermal monitoring crucial for safety and operational consistency.

These precision components are specifically intended for integration into systems such as battery management systems, large-scale battery energy storage systems, smart meters, and various industrial power supplies, inverters, and motor drives.