An Amplifier is an electronic instrument which is mainly used to increase the amplitude of a signal waveform in such a way that the other parameters of the waveform like frequency and the parameters like wave shape will not change and it will remain same. To be even simpler an amplifier works as a power modulator and it takes energy from the input and it distributes the energy with higher amplitude to the output. This article discusses about types of amplifiers and its practical examples.
Types of Amplifiers
The Amplifiers are classified among each other with certain criteria, but in general practice amplifiers are classified according to the input and output properties. Here are the types of amplifiers:
Voltage Amplifiers: The voltage amplifier itself is self explanatory to understand the function of the voltage amplifier. Mainly this amplifier is used to increase the voltage for the output and this type of amplifier is associated with character like high input impedance and low output impedance.
Current Amplifier: The current amplifier is mainly used for the purpose of increasing the input current and you can identify the current amplifier by its property like a low input impedance and high output impedance.
Transconductance Amplifier: This amplifier is really a wonderful one and it act according to the demand. In fact, it is the amplifier which will change the output current according to the corresponding change in the input current.
Transresistance Amplifier: This amplifier is mainly used to change the output voltage according to the change in the input voltage. In addition to the four basic types of amplifier there exists any other amplifier which comes in our day to day life.
Power Amplifiers: The last output stages of a circuit is the place where we will find the abundance use of the Power Amplifiers.
Operational Amplifiers (Op-Amps): This is another interesting amplifier where you will find both positive and negative input, but mainly it is used as a voltage amplifier.
Valve (or) Vacuum Tube Amplifiers: Here mainly the vacuum is used in order to get the desired voltage. However the other common amplifiers are transistor amplifiers, klystron, instrument amplifiers and distributed amplifiers.
Class of Amplifier: Whatever amplifiers available in the market are of not same type and the amplifiers are classified into various classes based upon certain parameter. And here we will just do that, we will educate you about the various classes of amplifier and how the amplifiers have been classified.
The amount of the output signal which varies within the amplifier circuit is one of the important characters of every amplifier and all the amplifiers are classified into various classed based on this parameter. In addition to the above other parameters like linear with very low efficiency, to entirely non-linear are the other parameter based on which the amplifiers are classified.
Amplifiers are initially categorized into two groups, out of which the first group of amplifiers are classified according to their controlled conduction angle amplifiers. Under this class the amplifiers are A, B, AB and C. In fact, some of the people also call this class of amplifier as the fully ON or fully OFF amplifier.
The other groups of amplifiers are called as “switching” amplifier and amplifiers of class D, E, F, G, S, T and other classes come under this group. The pulse width modulation (PWM) to constantly switch the signal between “fully-ON” and “fully-OFF” is the main character of this group of amplifiers and this character has made this particular class of amplifier very useful.
Class D Amplifier
The class d amplifier is the class of amplifier which comes with frequent use and this class is mainly used for portable and compact high-power applications. Again the class d amplifier is sub categorized into two types as the modern and traditional class d amplifier. Out of these two the traditional class d amplifier is the class where external lowpass is very much required filter to extract the audio signal from the pulse-width-modulated however in case of the modern class d amplifier the advanced modulation techniques is embedded within it.
Whatever be the class of the amplifier, but both the kind of d class of amplifier is very capable in eliminating the need for external filtering and reducing electromagnetic interference (EMI) as per the requirement.
The class d amplifier also got another common name as the electronic amplifier. To be honest the class d amplifier has no role to play when it comes to the digital aspect and it is because of the reason that the class of amplifier are not at all driven by coherent binary data. In fact the d class act in the in the fully ON-region or fully OFF-region. We can conclude that the class d amplifiers are non-linear switching amplifier.
Class A Amplifier
The class a amplifier has been accepted by all due to its configuration and simple arrangement. The ‘a’ in the class a amplifier denotes something and it indicates that it is the best class amplifier among all the main characteristic of this class an amplifier is the output where the transistor is ON full time and the output current flows for the entire cycle, hence it has been accepted widely. The low signal distortion levels probably the other reason for which it has been a popular class of amplifier.
In addition to the above the highest linearity over the other amplifier classes is the another USP of this class amplifier which has made it the most popular. In technical term the class an amplifier is more prominent ion the linear portion of the characteristic curve and from there the efficiency comes out.
The overall conversion efficiency is very low compared to the other amplifiers is the major disadvantage found with the class an amplifier, however this can be overlooked by the other superlative performance of this amplifier. The high fidelity along with totally immune to crossover distortion is the other important aspects of the class an amplifier which is not seen in the case of the other.
Class C Amplifier
The class c amplifier is a class among all and it is characterized by the greatest efficiency with the poorest linearity and this aspect has made this class of amplifier as the most accepted one. In case of the class c amplifier you will be able to note the performance of the transistor, which acts as the most active element. In fact the class c amplifier has been designed in such a way that it does not fit suit to the audio application. Yes, the distortion fact of the class c amplifier makes it unfit for the audio purpose.
The class c amplifier has got extensive application in case of the radio frequency and RF oscillators as well. The output of the c class amplifier is used in the LS resonant circuit.
If you will observe the graph of the class c amplifier you will come to know the technical aspects of the amplifier. In fact, from the graph it is clear and evident that some part of the input signal will miss from the output curve of the graph. From all aspects the class c amplifier is considered as the most used one.
This is all about types of amplifiers which includes voltage amplifier, current amplifier, transconductance amplifier, voltage amplifier, current amplifier, transresistance amplifier, power amplifier and operational amplifier. We hope that you have got a better understanding of this concept types of amplifiers.Furthermore, any doubts regarding this topic or any electronics and electrical projects please give your feedback by commenting in the comment section below.
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