What are the categories of sensors?
There are many kinds of sensors and various classification methods. The following are the common classification methods and their main types:
1. By Measured Physical Quantity (Application Target)
- Temperature Sensors: Thermocouples, thermistors, infrared sensors.
- Pressure Sensors: Piezoelectric, piezoresistive, capacitive sensors.
- Light Sensors: Photoresistors, photodiodes, CCD/CMOS (image sensors).
- Motion Sensors: Accelerometers, gyroscopes, displacement sensors.
- Force/Torque Sensors: Load cells, torque sensors.
- Magnetic Sensors: Hall effect sensors, magnetoresistive sensors.
- Chemical Sensors: Gas sensors (e.g., CO₂, formaldehyde), pH sensors.
- Biological Sensors: Glucose sensors, DNA sensors, heart rate sensors.
- Humidity Sensors: Capacitive, resistive humidity sensors.
- Acoustic Sensors: Microphones, ultrasonic sensors.
2. By Working Principle
- Resistive Sensors: Detect via resistance changes (e.g., strain gauges, thermistors).
- Capacitive Sensors: Utilize capacitance changes (e.g., liquid level sensors, touchscreens).
- Inductive Sensors: Based on electromagnetic induction (e.g., proximity switches).
- Piezoelectric Sensors: Use piezoelectric effects (e.g., pressure/vibration detection).
- Photoelectric Sensors: Rely on photoelectric effects (e.g., photodiodes, fiber-optic sensors).
- Thermoelectric Sensors: Leverage thermoelectric effects (e.g., thermocouples).
- Magnetoelectric Sensors: Detect magnetic field changes (e.g., Hall sensors).
- Chemical/Biological Sensors: Use chemical reactions or bio-recognition (e.g., enzyme electrodes, gas sensors).
3. By Output Signal Type
- Analog Sensors: Output continuous signals (e.g., voltage, current).
- Digital Sensors: Output discrete signals (e.g., switch signals, digital codes).
- Pulse/Frequency Sensors: Generate pulse/frequency signals (e.g., tachometers).
4. By Power Supply
- Active Sensors: Require external power (e.g., most electronic sensors).
- Passive Sensors: Self-powered (e.g., thermocouples, piezoelectric sensors).
5. By Application Field
- Industrial Sensors: Pressure, flow, temperature sensors (for automation).
- Medical Sensors: Pulse oximeters, ECG electrodes, glucose monitors.
- Automotive Sensors: Oxygen sensors, tire pressure monitors, ADAS (radar, cameras).
- Environmental Sensors: PM2.5 detectors, water quality sensors, weather stations.
- Consumer Electronics Sensors: Gyroscopes in smartphones, fingerprint scanners, ambient light sensors.
6. By Material/Structure
- MEMS Sensors: Micro-electromechanical systems (e.g., accelerometers, microphones).
- Fiber-Optic Sensors: Use optical signals (e.g., temperature/strain detection).
- Flexible Sensors: Bendable materials (e.g., electronic skin, wearables).
7. By Intelligence Level
- Traditional Sensors: Output raw signals.
- Smart Sensors: Integrated signal processing, self-calibration, or communication (e.g., IoT sensors).
8. Other Special Classifications
- Contact vs. Non-contact: Contact temperature sensors vs. infrared sensors.
- Environmental Adaptability: Waterproof, explosion-proof, high-temperature-resistant sensors (e.g., industrial-grade).
Summary
Sensor classifications are not rigid—many overlap categories (e.g., a MEMS accelerometer is both a motion sensor and a digital sensor). Selection depends on measurement requirements, environment, accuracy, and cost.
传感器种类繁多，分类方式多样，以下为常见的分类方法及其主要类型：
1. 按被测物理量（应用目标）分类
- 温度传感器：热电偶、热敏电阻、红外传感器。
- 压力传感器：压电式、压阻式、电容式传感器。
- 光传感器：光敏电阻、光电二极管、CCD/CMOS（图像传感器）。
- 运动传感器：加速度计、陀螺仪、位移传感器。
- 力学传感器：力传感器、扭矩传感器、称重传感器。
- 磁传感器：霍尔传感器、磁阻传感器。
- 化学传感器：气体传感器（如CO₂、甲醛）、pH传感器。
- 生物传感器：血糖传感器、DNA传感器、心率传感器。
- 湿度传感器：电容式湿度传感器、电阻式湿度传感器。
- 声学传感器：麦克风（声音传感器）、超声波传感器。
2. 按工作原理分类
- 电阻式传感器：通过电阻变化检测（如应变片、热敏电阻）。
- 电容式传感器：利用电容变化（如液位传感器、触摸屏）。
- 电感式传感器：基于电磁感应（如接近开关）。
- 压电式传感器：利用压电效应（如压力、振动检测）。
- 光电式传感器：基于光电效应（如光敏二极管、光纤传感器）。
- 热电式传感器：利用热电效应（如热电偶）。
- 磁电式传感器：基于磁场变化（如霍尔传感器）。
- 化学/生物传感器：通过化学反应或生物识别（如酶电极、气体传感器）。
3. 按输出信号类型分类
- 模拟传感器：输出连续信号（如电压、电流）。
- 数字传感器：输出离散信号（如开关信号、数字编码）。
- 脉冲/频率传感器：输出脉冲或频率信号（如转速传感器）。
4. 按能源供应方式分类
- 有源传感器：需外部电源供电（如大多数电子传感器）。
- 无源传感器：无需外部电源，自供能（如热电偶、压电传感器）。
5. 按应用领域分类
- 工业传感器：压力、流量、温度传感器（用于自动化控制）。
- 医疗传感器：血氧仪、心电图电极、血糖仪。
- 汽车传感器：氧传感器、胎压监测、ADAS（雷达、摄像头）。
- 环境监测传感器：PM2.5检测、水质传感器、气象站。
- 消费电子传感器：手机中的陀螺仪、指纹识别、环境光传感器。
6. 按材料与结构分类
- MEMS传感器：微机电系统（如加速度计、麦克风）。
- 光纤传感器：基于光信号传输（如温度、应变检测）。
- 柔性传感器：可弯曲材料制成（如电子皮肤、可穿戴设备）。
7. 智能化程度分类
- 传统传感器：仅输出原始信号。
- 智能传感器：集成信号处理、自校准或通信功能（如IoT传感器）。
8. 其他特殊分类
- 接触式与非接触式：如温度传感器（接触） vs 红外传感器（非接触）。
- 环境适应性：防水、防爆、耐高温传感器（如工业防爆型）。
总结
传感器的分类并非绝对，同一传感器可能归属多个类别（例如MEMS加速度计既是运动传感器，又是数字传感器）。选择时需结合被测对象、环境条件、精度需求及成本等因素综合考虑。