Working Principle of instruments

Question

Accepted Answer

The working principle of instruments involves the use of various physical or electrical phenomena to measure or control variables.

Instruments use principles such as pressure, temperature, flow, level, or electrical signals to perform their functions.
For example, a pressure gauge works based on the principle of elastic deformation of a diaphragm or Bourdon tube.
A thermocouple measures temperature by utilizing the Seebeck effect, where a voltage is generated when two dissimilar metals are joined at different temperatures.
Flow meters can operate based on principles like differential pressure, electromagnetic induction, or ultrasonic waves.
Level sensors can use principles like buoyancy, capacitance, or ultrasonic waves to determine the level of a substance.
Instruments may also employ electrical signals, such as current or voltage, to measure or control variables.
For instance, a PID controller uses feedback control to maintain a desired value by adjusting the output based on the difference between the setpoint and the measured value.

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