Instrumentation Term 3: Pressure Sensors

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Questions and Answers

What is the primary mechanism used by a potentiometric pressure sensor to convert pressure into an electrical signal?

Moving a wiper arm on a resistive element (correct)

Changing the resistance of a strain gauge

Varying the inductive coupling between the transformer primary and secondary

Generating a piezoelectric charge

What is a major disadvantage of potentiometric pressure sensors?

Repeatability and Hysteresis Errors - Low Performance (correct)

High cost

Sensitivity to temperature changes

Limited range of measurement

What is the principle of operation of an inductive pressure sensor?

Using the LVDT of a moving core to vary the inductive coupling between the transformer primary and secondary (correct)

Generating a piezoelectric charge

Moving a wiper arm on a resistive element

Varying the resistance of a strain gauge

Which type of pressure sensor uses a piezoelectric material to generate a charge in response to pressure changes?

Piezoelectric Pressure Sensor Signup and view all the answers

What is a critical consideration in instrumentation design when using pressure sensors?

Temperature compensation Signup and view all the answers

Which type of pressure sensor is commonly used in industrial applications where high accuracy and precision are required?

Strain Gauge Pressure Sensor Signup and view all the answers

What type of pressure sensor is used when it is not possible to have the sensor directly open to the reference pressure?

Sealed pressure sensor Signup and view all the answers

What does the maximum pressure of a sensor indicate?

The absolute maximum value of pressure in which the device can reliably function Signup and view all the answers

What is the primary function of an absolute pressure sensor?

To measure pressure relative to a vacuum Signup and view all the answers

What is the difference between the maximum pressure that the sensor can measure and zero pressure?

Full scale Signup and view all the answers

What type of pressure sensor measures the difference in pressure between two points in a system?

Differential pressure sensor Signup and view all the answers

What does the sensor type specify in a pressure sensor?

The type of pressure for which the sensor is designed to operate Signup and view all the answers

What is the typical size of a sensor chip?

2 mm × 2 mm Signup and view all the answers

What is the purpose of providing the operating pressure range of a sensor?

To provide the range of pressures over which the sensor can operate and generate a signal output Signup and view all the answers

What type of pressure sensor provides a pressure measurement relative to the local atmospheric pressure?

Gauge pressure sensor Signup and view all the answers

What does the output type of a pressure sensor describe?

The general nature of the output signal characteristics Signup and view all the answers

What type of sensor is used to measure pressure?

All of the above Signup and view all the answers

What is the primary advantage of piezoelectric pressure sensors?

High sensitivity Signup and view all the answers

Study Notes

Parts of a General Purpose Pressure Sensor

A pressure sensor consists of a sensing element, signal conditioning, and output stages.

Piezoelectric Pressure Sensor

Uses piezoelectric materials to generate an electric charge in response to changes in pressure.

Pressure Sensors

There are different types of pressure sensors, including potentiometric, inductive, piezoresistive, and IC sensors.

Potentiometric Pressure Sensors

Uses a Bourdon tube, capsule, or bellows to drive a wiper arm on a resistive element.
Advantages: Relatively inexpensive sensors used for coarse measurements.
Disadvantages: Repeatability and hysteresis errors, low performance.

Inductive Pressure Sensors

Uses the LVDT of a moving core to vary the inductive coupling between the transformer primary and secondary.

Piezoresistive Sensors

Also known as IC sensors, solid-state sensors, or monolithic sensors.
Use a single-crystal silicon sensor chip, typically 80 × 80 mils or 2 mm × 2 mm in size.

Pressure Sensing Methods

There are three main methods: absolute, gauge, and differential pressure sensing.

Absolute Pressure Sensors

Provide a pressure measurement relative to a reference of zero pressure, which is as close as possible to a vacuum.

Gauge Pressure Sensors

Provide a pressure measurement relative to the local atmospheric pressure.

Differential Pressure Sensors

Measure the difference in pressure between two points in a system.

Sealed Pressure Sensors

Used when it is desired to obtain a pressure measurement relative to a reference value, but where it is not possible to have the sensor directly open to that reference pressure.

Pressure Sensor Specifications

Sensor type reflects the pressure type for which the sensor is designed to operate.
Operating pressure range provides the range of pressures over which the sensor can operate and generate a signal output.
Maximum pressure is the absolute maximum value of pressure in which the device can reliably function without damaging the sensor.
Full scale is the difference between the maximum pressure that the sensor can measure and zero pressure.
Output type describes the general nature of the output signal characteristics from the pressure sensor.

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Description

Test your knowledge of pressure sensors, including general purpose pressure sensors, piezoelectric pressure sensors, and types of electronic pressure sensors. This quiz covers the basics of instrumentation in engineering.