Transducer and its type

Transducer

A transducer is an electronic device that converts energy from one form to another. The physical quantity which is to be measured can be pressure, level, temperature, displacement, etc. The output which is obtained from the transducer is in the electrical form and is equivalent to the measured quantity.

Parts of transducer-

1. Sensing or Detector Element  – It is the part of the transducers which give the response to the physical sensation. The response of the sensing element depends on the physical phenomenon.
2. Transduction Element  – The transduction element converts the output of the sensing element into an electrical signal. This element is also called the secondary transducer.

Type of transducer:-

1) primary transducer:-

it consists of electrical as well as the mechanical device. The mechanical device converts the physical quantity to be measured into a mechanical signal. Such a mechanical device is called the primary transducers because they deal with the physical quantity to be measured. The primary transducer is that which comes in contact with the medium being measured.

example-bourdon tube 

2) secondary transducer:-

The transducer which converts the output of the first transducer into an electrical output called a secondary transducer. The secondary transducer does not come in direct contact with the medium being measured but transduces the output of the primary transducer into another form of energy.

example- LVDT

another classification of the transducer on the basis of power supply-

1) active transducer:-

The transducer which does not require any power source for their operation is known as an active transducer. They work on the energy conversion principle. They produce an electrical signal proportional to the input (physical quantity).

example-a piezoelectric crystal is an active transducer.

2) passive transducer:-

The transducer which requires the power source from an external supply source for their operation is known as an active transducer.

they are also known as an external transducer.

example-capacitive transducers.

On the basis of the output of measured value-

1) Analog transducer:-

The analog transducer is that the transducer which changes the input quantity into a continuous function.

example- analog pressure gauge, analog temperature gauge

2) digital transducer:-

these type of transducer converts the input signal into a digital signal or in the form of the pulse.

example- LVDT(linear variable differential transformer )

Difference between sensor and transducer-

The transducer is a device which can converts energy from one form to another form whereas the sensor is the device which converts the physical input data into the electrical signal.

 The sensor detects the energy level and changes it into an electrical signal which is easily measured by the digital meters. The transducer transfers the energy either in the same form or another.

The advantage of transducer-

1. The attenuation and amplification of the electrical signals are very easy.
2. The electrical signal produces less friction error.
3. The small power is required for controlling the electrical systems.
4. The electrical signals are easily transmitted and processed for measurement.
5. The component used for measuring the electrical signal is very compact and accurate.
6. The electrical signals are used in telemetry.