A pressure sensor is any device that measures pressure and converts it to an electrical signal. All transducers, transmitters, and switches are sensors, but not all sensors are transducers, transmitters, or switches.
For example, in a thermocouple the electrical potential difference is produced due to temperature difference across its terminals. So, thermocouple is an temperature transducer.
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna.
Transducers are often employed at the boundaries of automation, measurement, and control systems, where electrical signals are converted to and from other physical quantities (energy, force, torque, light, motion, position, etc.). The process of converting one form of energy to another is known as transduction.
A potentiometer sensor measures the distance or displacement of an object in a linear or rotary motion and converts it into an electrical signal.
A pressure transmitter is a mechanical device that measures the expansive force of a liquid or gaseous sample.
A temperature transmitter is an electrical instrument that interfaces a temperature sensor for example a thermocouple, RTD, or thermistor sensor to a measurement or control device like a PLC, DCS, PC, loop controller, data logger, display, recorder, etc.
A transducer is an electronic device that converts energy from one form to another. Common examples include microphones, loudspeakers, thermometers, position and pressure sensors, and antenna. Among the worst transducers, in terms of efficiency, are incandescent lamps.
An actuator is a device that converts energy into motion. Therefore, it is a specific type of a transducer. When the output of the transducer is converted to a readable format, the transducer is called a sensor. A sensor is a device that receives and responds to a signal.
Example of passive transducer is LVDT (linear variable differential transformer). It generates electric current or voltage directly in response to environmental stimulation. It gives a change in some passive electrical quantity, such as capacitance, resistance or inductance, as a result of stimulation.
The most crucial difference between the active and passive transducer is that the active transducer does not use any external power source for producing the output, whereas the passive transducer requires the additional energy source for working.
When sensors are used at input of a system, actuators are used to perform output function in a system as they control an external device. Transducers are the devices that convert energy in one form into another form. Generally the energy is in the form of a signal.
In transducer. The active transducers generate electric current or voltage directly in response to stimulation. An example is the thermocouple; here, the fact that a current will flow in a continuous circuit of two metals, if the two junctions are at different temperatures, is used to generate electricity.…
Different Types of Sensors
- Temperature Sensor.
- Proximity Sensor.
- Accelerometer.
- IR Sensor (Infrared Sensor)
- Pressure Sensor.
- Light Sensor.
- Ultrasonic Sensor.
- Smoke, Gas and Alcohol Sensor.
Pressure transmitters are divided into three types: Absolute Transmitter: This transmitter take vacuum pressure as its base, and then measures process pressure. Gauge Transmitter: This type measures process pressure with the location's atmospheric pressure as a base.
When selecting a pressure transducer, keep these five criteria in mind:
- Application and measurement type. Common type of pressure measurement include: Absolute, gauge, differential, vacuum, bidirectional, and sealed gage.
- Pressure range.
- Process media.
- Temperature range and installation environment.
- Accuracy.
These are:
- Potentiometric pressure sensors.
- Inductive pressure sensors.
- Capacitive pressure sensors.
- Piezoelectric pressure sensors.
- Strain gauge pressure sensors.
- Variable reluctance pressure sensors.
There are five types of pressure transducers: Standard, Top Mount, Side Mount, High Accuracy and High Temperature. Pressure transducers can be internal (inside) or external (outside) depending on the type of pressure transducer.
An oil pressure switch is a protection device for an engine. Its a type of oil pressure sensor. As the name suggests the oil pressure switch is a mechanical device that has a switch inside.
The transducers can be classified broadly i. On the basis of transduction form used ii. As primary and secondary transducers iii. A component whose output energy is supplied entirely by its input signal (physical quantity under measurement) is commonly called a „passive transducer?.
Following is a list of some of the important static characteristics of transducers.
- Sensitivity.
- Linearity.
- Resolution.
- Precision (Accuracy)
- Span and Range.
- Threshold.
- Drift.
- Stability.
An example of an inherently bidirectional transducer is an antenna, which can convert radio waves (electromagnetic waves) into an electrical signal to be processed by a radio receiver, or translate an electrical signal from a transmitter into radio waves.
Active Transducer – The transducer which does not require the external power source is known as the active transducer. Such type of transducer develops theirs owns voltage or current, hence known as a self-generating transducer. The output signal is obtained from the physical input quantity.
Which of the following is an analog transducer? Explanation: Analog transducers convert physical quantity to analog signals while digital transducers convert physical quantity to digital signals. Strain gauge is an example of an Analog transducer. That is, it converts force into electric signals.
Basic Requirements Of a Transducer (cont'd)
- Ruggedness. It should be capable of withstanding overload and some safety arrangement should be provided for overload protection.
- Linearity. Its input-output characteristics should be linear and it should produce these characteristics in symmetrical way.
- Repeatability.
