Sensors: From Definition to Industrial Applications

1. Definition and Application of Sensors

A sensor is a device or instrument that detects and measures physical properties, environmental conditions, or changes in its surroundings and convert the sensed information into electrical signals or other required forms of information output to meet the needs of information transmission, interpreting, processing, storage, display, and recording or used for various purposes.

Sensors have become integral across diverse industries, especially industrial production sectors such as new energy vehicles, rail transit, photovoltaic energy, and low-voltage electric energy. They extend into broader fields like space development, ocean exploration, medical diagnosis, and bioengineering.

Typical sensor testing covers general inspection, measurement performance, influence quantity, time performance, safety, mechanical aspects, environmental tolerance, and EMC testing, among others.

2. Industrial Sensors

2.1 Current Sensor

In industrial settings, current sensors are widely employed, especially in fields like motors, new energy vehicles, household appliances, smart grids, and wind power generation. The annual demand for magnetic sensors exceeds tens of billions. As application requirements evolve, sensors now handle increasingly complex signals with features like wide dynamic range and nonlinearity. Testing equipment must adapt to achieve broad measurement limits and broadband output while ensuring accuracy and stability.

2.2 DC Shunt

A shunt is a DC current measurement instrument designed on the principle of voltage generation across a resistor when DC current passes through it. Functioning as a low-resistance resistor, the shunt measures the voltage drop across it. Using Ohm's law, the current flowing through the resistor can be calculated, enabling precise current detection. In applications like new energy vehicle charging stations, external shunts leverage this principle for current testing and electric energy measurement.

2.3 Voltage Sensor

A voltage sensor detects and converts measured voltage into a usable output signal. Essential for tracking high-speed AC and DC voltage signals in automatic detection and control, voltage sensors excel in accuracy, speed, linearity, frequency range, overload resistance, and energy efficiency compared to traditional transformers and shunts. They find extensive applications in power systems, electronics, inverters, switch power supplies, and AC frequency conversion speed regulation. Common types include voltage transformers, Hall voltage sensors, and light voltage sensors.