Resistive Detection Method
The resistive detection method is one of the most fundamental detection techniques. Its principle is simple: it senses changes in a physical quantity under measurement by measuring corresponding changes in electrical resistance. This method leverages the characteristic property of materials wherein their resistance varies in response to changes in external conditions.
Capacitive Detection Method
The capacitive detection method utilizes the principles of capacitors. As is known, the capacitance value depends on the area of the capacitor plates, the distance between them, and the dielectric constant of the insulating medium. When any of these parameters undergo a change, the capacitance value changes accordingly.
Inductive Detection Method
The inductive detection method is primarily applied to the detection of metal objects and the measurement of displacement. Its operating principle is based on electromagnetic induction: when a metal object approaches an inductive sensor, eddy currents are induced within the metal, thereby altering the sensor's inductance.
Piezoelectric Detection Method
The piezoelectric detection method harnesses the piezoelectric effect: certain specific materials generate an electric charge when subjected to mechanical stress (pressure), and conversely, undergo deformation when subjected to an electric field. This electromechanical conversion property renders this method particularly useful for dynamic measurements.
Photoelectric Detection Method
The photoelectric detection method is a technique that utilizes optical principles for detection. It employs a detection system comprising a light source, an optical path, and a photosensitive element to sense the parameter under measurement based on variations in light signals.
Ultrasonic Detection Method
The ultrasonic detection method utilizes the propagation characteristics of ultrasonic waves within a medium for detection. Ultrasonic waves are sound waves with frequencies exceeding the range of human hearing; they are characterized by properties such as excellent directionality and strong penetrating power.
Hall Effect Detection Method
The Hall effect detection method is based on the principle of the Hall effect: when an electric current flows through a conductor placed within a magnetic field, a voltage difference is generated in a direction perpendicular to both the current and the magnetic field. This resulting Hall voltage is directly proportional to the strength of the magnetic field.
Thermocouple Detection Method
The thermocouple detection method is one of the most widely used techniques for temperature measurement. Its principle is based on the thermoelectric effect: when a closed circuit composed of two different metals is subjected to a temperature difference between its two junctions, a thermoelectric potential (voltage) is generated.
Semiconductor Detection Method
The semiconductor detection method utilizes the specific properties of semiconductor materials for detection. Semiconductor materials are highly sensitive to external factors-such as temperature, light exposure, and gases-making them exceptionally well-suited for the fabrication of various types of sensors.
Fiber-Optic Sensing
Fiber-optic sensing is a detection method that has developed rapidly in recent years. It utilizes changes in the propagation characteristics of light within an optical fiber to sense external physical quantities.