A guide for engineers balancing performance, reliability, and manufacturability across today’s smart systems
By Barry Brents, Littelfuse, Inc.
Selecting the ideal sensor for a new design is rarely straightforward. For R&D and electronics design engineers, the decision extends beyond price or availability—it’s about ensuring precision, reliability, and performance in demanding real-world conditions. Whether developing next-generation appliances, automotive electronics, or industrial automation systems, sensors define how your product perceives and interacts with its environment.
Understanding the available sensor types, their operating principles, and supplier capabilities can help engineers make design choices that accelerate development while reducing long-term costs and risks.
The Expanding Role of Sensors in Modern Design
Sensors are the foundation of every intelligent system. They convert physical phenomena—such as temperature, proximity, or magnetic field strength—into actionable electrical signals. Their ubiquity across industries underscores their importance:
- Appliances: From smart refrigerators to compact kitchen tools, sensors regulate temperature, detect motion, and ensure user safety.
- Building and Industrial Automation: Sensors enable adaptive lighting, efficient HVAC control, and security monitoring.
- Automotive and Electric Vehicles (EVs): In connected vehicles, sensors are essential for safety, energy management, and user experience. They monitor everything from wheel speed and brake pressure to battery temperature and motor position.
- Factory Automation and Robotics: Sensors guide machinery, maintain process accuracy, and ensure worker safety, forming the backbone of Industry 4.0.
As designs become more compact, energy-efficient, and interconnected, engineers must select sensors that deliver precise performance within tighter design constraints.
Six Core Sensor Types in Electronics Design
While sensors span a wide range of technologies, six categories dominate electronics applications. Understanding their strengths helps engineers choose the right one for their design priorities—whether that’s low power, precision, isolation, or size.
1. Reed Switches
Reed switches contain two ferromagnetic blades sealed in a nitrogen-filled glass capsule to prevent corrosion. When a magnetic field is applied, the blades attract and close, completing the circuit. These switches operate without external power, offering exceptional reliability and efficiency for battery-powered or safety-critical designs.
2. Hall Effect Sensors
Based on semiconductor physics, Hall sensors output a voltage proportional to the strength of a magnetic field. They require signal conditioning and temperature compensation but provide continuous detection for applications such as rotary encoders, linear positioning, and non-contact sensing. Their solid-state nature ensures durability and long operational life.
3. Reed Relays
Reed relays integrate a reed switch with a coil, providing galvanic isolation between control and load circuits. Their compact form factor, low contact resistance, and high insulation resistance make them ideal for test and measurement systems, medical instruments, and industrial controls that require precise switching with minimal power.
4. Tunneling Magnetoresistance (TMR) Switches
Combining magnetic tunneling technology with CMOS integration, TMR switches deliver ultra-low power consumption and high magnetic sensitivity. They integrate on-chip voltage generation, signal amplification, and temperature compensation with the TMR sensor to maintain accuracy across wide operating ranges. This makes them particularly attractive for IoT devices, smart meters, and compact electronics.
5. Thermistors
Thermistors change resistance with temperature—decreasing for NTC (negative temperature coefficient) types and increasing for PTC (positive coefficient) types. They provide high sensitivity and excellent accuracy over limited ranges, making them suitable for precise temperature control in appliances, battery packs, and environmental sensing.
6. Platinum Resistance Temperature Detectors (Pt-RTDs)
Pt-RTDs offer near-linear resistance change over a broad range (−70 °C to 500 °C for a thin-film Pt-RTD ), making them ideal for industrial systems requiring stable and repeatable temperature monitoring. Their reliability and long-term drift resistance make them a go-to for critical process and instrumentation applications.
Four Key Questions to Guide Sensor Selection
Selecting the correct sensing technology is just one part of the design equation. Choosing the right supplier can significantly influence engineering efficiency, customization options, and long-term supply assurance.
1. Does the supplier offer a complete sensor portfolio?
Working with a supplier that manufactures multiple sensor types—from magnetic to temperature sensors—can simplify sourcing and ensure design consistency. It also increases the likelihood of cross-technology innovation and simplifies qualification testing. A diverse product portfolio often signals stronger application knowledge and long-term product continuity.
2. What level of application support is available?
Supplier application engineers can be invaluable allies. Their insight into environmental factors—such as vibration, EMI, and temperature variations—can help identify potential issues before prototyping begins. Early collaboration can reduce design iterations and accelerate time to market.
3. Are custom-engineered solutions an option?
Off-the-shelf sensors don’t always fit unique requirements. When faced with dimensional constraints, specific sensitivity needs, or connector compatibility challenges, a supplier offering custom design capabilities—supported by 3D CAD and simulation tools—can provide tailored solutions without compromising performance or manufacturability.
4. Can the supplier support your production demands?
Even the most advanced design can be derailed by supply chain delays. Partnering with a manufacturer that maintains global production capacity, scalable output, and proven logistics support can protect your project timelines. During periods of rapid demand growth, this flexibility ensures your design transitions smoothly from prototype to full-scale production.
Design Efficiency Starts with the Right Supplier
A sensor that perfectly fits your specifications but comes from an unreliable or limited supplier can create downstream risks. Conversely, a slightly higher initial cost from a well-supported, high-capacity supplier may yield significant long-term savings in development time, warranty claims, and customer satisfaction.
Today’s leading component manufacturers combine global production capabilities with advanced design support. Many modern facilities use automated testing and calibration to ensure consistent quality across product lines. Engineers who prioritize these attributes during supplier selection often find that their total cost of ownership decreases—even if individual sensor prices are higher.
Designing for Performance, Reliability, and Scalability
Selecting sensors for modern applications demands a balance between technical precision and supply-chain resilience. Engineers must weigh factors like sensitivity, accuracy, operating environment, and packaging constraints against broader business considerations such as lifecycle availability and customization options.
Ultimately, the most successful sensor designs stem from informed partnerships. When engineers collaborate early with suppliers that combine engineering expertise, simulation capabilities, and scalable manufacturing, they unlock new levels of design efficiency and performance—while reducing risk across the product lifecycle.
For more in-depth information, download “Eight Considerations When Purchasing Sensors” and the “Sensing Products Selection Guide,” courtesy of Littelfuse, Inc.
About the author
Barry Brents is a Field Application Engineer at Littelfuse. He is a former U.S. Navy nuclear submarine officer and a licensed professional electrical engineer in Colorado and California. He has been with Littelfuse for 35 years (including acquisitions), and his current responsibilities include technical support, design assistance, and training for customers and salespeople. Barry received his B.S.E.E. from Texas Tech University.
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