How does a Wheatstone bridge pressure sensor change resistance with applied pressure?
1 Answer
A Wheatstone bridge pressure sensor, also known as a strain gauge pressure sensor, operates based on the principle that the resistance of a material changes with applied pressure or strain. These sensors are widely used in various industries to measure pressure in different applications.
The basic setup of a Wheatstone bridge pressure sensor includes four resistors arranged in a diamond configuration, forming two parallel branches. The resistors can be strain gauges, which are small devices made of a wire or a thin metal foil that experiences changes in resistance when subjected to strain or pressure.
Here's how a Wheatstone bridge pressure sensor changes resistance with applied pressure:
Strain effect: When pressure is applied to the sensor, it undergoes deformation or strain. This strain causes the metal foil or wire in the strain gauge to stretch or compress slightly, altering its original shape.
Resistance change: The strain experienced by the strain gauge changes its electrical resistance. In most cases, when the strain gauge is stretched, its length increases, and thus its cross-sectional area decreases, leading to an increase in resistance. Conversely, when compressed, its length decreases, and its cross-sectional area increases, resulting in a decrease in resistance.
Bridge circuit: The four resistors in the Wheatstone bridge are arranged in a balanced configuration. When no pressure is applied to the sensor, the bridge is balanced, and the output voltage across the bridge is zero.
Unbalanced bridge: With applied pressure, the resistance of the strain gauge changes, causing an imbalance in the bridge circuit. As a result, a non-zero voltage difference appears across the output terminals of the bridge.
Output signal: The output voltage of the Wheatstone bridge is directly proportional to the applied pressure or strain. This voltage can be measured and converted into an equivalent pressure value using appropriate calibration techniques.
Sensitivity and calibration: The sensitivity of the pressure sensor depends on the characteristics of the strain gauge used, the material it's made of, and the mechanical design of the sensor. Calibration is essential to establish a linear relationship between the pressure applied and the corresponding output voltage.
By measuring the output voltage of the Wheatstone bridge, the pressure sensor can accurately determine the applied pressure or strain, making it a reliable and commonly used method for pressure measurement in various industrial and scientific applications.
The basic setup of a Wheatstone bridge pressure sensor includes four resistors arranged in a diamond configuration, forming two parallel branches. The resistors can be strain gauges, which are small devices made of a wire or a thin metal foil that experiences changes in resistance when subjected to strain or pressure.
Here's how a Wheatstone bridge pressure sensor changes resistance with applied pressure:
Strain effect: When pressure is applied to the sensor, it undergoes deformation or strain. This strain causes the metal foil or wire in the strain gauge to stretch or compress slightly, altering its original shape.
Resistance change: The strain experienced by the strain gauge changes its electrical resistance. In most cases, when the strain gauge is stretched, its length increases, and thus its cross-sectional area decreases, leading to an increase in resistance. Conversely, when compressed, its length decreases, and its cross-sectional area increases, resulting in a decrease in resistance.
Bridge circuit: The four resistors in the Wheatstone bridge are arranged in a balanced configuration. When no pressure is applied to the sensor, the bridge is balanced, and the output voltage across the bridge is zero.
Unbalanced bridge: With applied pressure, the resistance of the strain gauge changes, causing an imbalance in the bridge circuit. As a result, a non-zero voltage difference appears across the output terminals of the bridge.
Output signal: The output voltage of the Wheatstone bridge is directly proportional to the applied pressure or strain. This voltage can be measured and converted into an equivalent pressure value using appropriate calibration techniques.
Sensitivity and calibration: The sensitivity of the pressure sensor depends on the characteristics of the strain gauge used, the material it's made of, and the mechanical design of the sensor. Calibration is essential to establish a linear relationship between the pressure applied and the corresponding output voltage.
By measuring the output voltage of the Wheatstone bridge, the pressure sensor can accurately determine the applied pressure or strain, making it a reliable and commonly used method for pressure measurement in various industrial and scientific applications.