Transducer

In this article, we will discuss the important terms that are often used in electronic communication systems. The electronic communication system is a wide range of fields with various electrical and electronic components. In that, transducers play a significant role. We can see the concept of the transducer types in detail. We also covered the concept of LVDT and the potentiometer.

Terms used in a communication system

In the electronic communication system, the electric circuits transmit, process, and receive the data. The transmission happens through the transmitter. The data processing occurs through the medium and gets accepted by the receiver. The data is transmitted in two forms: digital or analog form.

The Basic terminologies include communication medium, receiver, transmitter, transducer, amplitude, modulation, and bandwidth.

Communication medium

The communication medium is the channel used to transmit the signal from transmitter to receiver. An example is copper wire and satellite systems.

Signal

The signal is the information or data transmitted and received by the receiver. It is transmitted electronically, in digital format. There are two forms of signals: digital and analog. In analog signals, the current and voltage will have continuous variations. An example is a human voice. The variations will have 0 and 1 discrete values in the digital signals. An example is audio waves. 

Amplitude 

The amplitude is the signal height or strength in transmission. The signals should be strong in both transmission and reception. For this, the weak signal is amplified. This phenomenon is called amplification.

Attenuation

Attenuation is the process in which the amplification of the signal is decreased. It is attenuated when transmitted for long distances.

In this electronic communication system, we will discuss the important device, transducers.

Transducers

The transducer is the electrical device that transforms the physical quantity into electrical quantity. It consists of two elements: sensing and transduction. For example, the transducer transforms the non-electrical quantity like light and heat into electrical quantity.

Transducers types

The transducers are classified as below

• Active and passive transducers

• Analog and digital transducers

• Primary and secondary transducers

Active and passive transducers

Active transducers

The active transducers use the energy required for the transmission process. The output signal is produced from the energy of the physical quantity. It will not use an external power source. It is also called a self-generating type transducer.

Examples

• Accelerometer

• Tacho generator

• Thermocouple

• Piezoelectric transducers

• Photovoltaic cells

Passive transducers

The passive transducers use the external power supply for the signal transformation. It is also called an externally powered transducer.

Examples

• Capacitive transducers

• Potentiometer

• Resistive transducers

• Inductive transducers

Potentiometer

The potentiometer or a pot measures the displacement consisting of a wiper and resistive elements. The external power supply is required passively. The output voltage is directly linear or proportional to the displacement.

These potentiometers are simple in operation and have high electrical efficiency. It is cheap. But it requires a large force of wiper movement and has a limited lifetime.

Analog and digital transducers

Analog transducers

The input signal is converted into analog output using analog transducers. It is continuous-time in nature.

Examples

• Thermocouple

• Strain gauge

• Thermistor

• LVDT

Digital transducers

The input signal is converted into digital output by using digital transducers. It is non-continuous-time in nature.

Example

Photoelectric transducers

Primary and secondary transducers

Primary transducers

The primary transducers are directly connected to the measurable physical quantity.

Example

Bourdon tube in LVDT

Secondary transducers

The secondary transducers are not directly connected to the measurable physical quantity.

Example

LVDT

LVDT

LVDT means the linear variable differential transformer, which converts the linear motion into an electrical output voltage. The transformer has two windings such as primary and secondary windings. 

Here, the transformer’s primary windings are connected to the AC source. The measured displacement is applied to the soft iron core arm. This core is made up of nickel-iron. 

The output voltage E0 is the difference between the output voltage of secondaries, ES1 and ES2.

E0 = ES1 – ES2.

Conditions of output voltage

The E0 is positive when the core moves to left

The E0 is negative when the core moves to the right

Applications

• LVDT is used for displacement measurement.

• It is used for pressure measurement.

• The electrical voltage is converted into mechanical displacements with the help of LVDT.

Advantages of transducers

• Transducers simplify the attenuation and amplification process of the electrical quantities.

• The frictional effect is minimised.

• The electronic and electrical power is decreased.

• The transmission and processing of output were made easier.

Conclusion

Electronic communication systems transfer the data or information in the form of signals with the help of communication channels. The transducer is an important electronic component in an electric circuit, used for a wide range of applications. In this article, we have seen the types of transducers with their examples. These transducers are classified based on their functionality, power source, and structure. We have discussed the LVDT and potentiometer.