Most of the systems need at least one phase of amplification. Hence amplifiers can be used in almost all the electronic devices. These are the devices that raise the amplitude of the i/p signal. The o/p of the power supply is controlled by the Amplifier. These can only increase the amplitude and the other parameters like frequency and shape remain constant. The main function of an amplifier is to increase the amplitude of the signal without changing the parameters like the shape of the wave or frequency. Amplifiers are one of the most frequently used circuits in electronics and achieve a variety of functions in great several electronic systems. There are numerous types of amplifiers accessible. But they can be famous by the type of signal they amplify. The different types of amplifiers can be classified by the kind of function they execute. The important characteristics of an amplifier include bandwidth, noise, skew rate, gain, stability, linearity, efficiency, output dynamic range.
Types of Amplifiers and their Workings
Although amplifiers are sometimes categorized according to i/p and o/p parameters. They are four basic types, namely, current amplifier, a transconductance amplifier, voltage amplifier, trans-resistance amplifier. Apart from the basic forms, there are several other types of amplifiers classified by their operation, characteristics or application. Some of them are
The term AF stands for Audio frequency amplifiers, used to amplify signals in the human hearing range around 20Hz-20kHz, while some Hi-Fi AF (audio amplifiers) spread this range up to around 100kHz, whereas other audio amplifiers may control the limit of high frequency to 15kHz or less.
Voltage amplifiers are used to increase the low-level signals from microphones, disk pickups, and tape, etc. With additional circuitry they also execute functions like tone correction, equalization levels of signal and combining from different multiple inputs, they generally have a high voltage gain and output resistance is medium to high. Power amplifiers are used to get the amplified i/p from a sequence of voltage amplifiers, and then offer enough power to drive loudspeakers.
The term AF stands for intermediate frequencies are amplified by this amplifier. The applications of these amplifiers include TV, radar, and radio. They provide the maximum voltage amplification of a radio, TV or radar signal before the audio or video information carried by the signal is demodulated.
The frequency of operation is lesser than that of the received radio signal but higher than the audio or video signals finally produced by the system. The kind of equipment chooses the frequency at which intermediate frequency amplifiers operate.
The term RF stands for Radio Frequency amplifiers are adjusted amplifiers in which the frequency of operation is directed by a tuned circuit. This tuned circuit may or may not be changeable relying on the purpose of the amplifier. Bandwidth also depends on usage and may be comparatively wide, or thin. The input resistance is usually low.
A special feature of radio frequency amplifiers where they are used in the initial stages of a receiver is low noise performance. It is significant that background noise generally formed by any electronic device, is kept to a smallest because the amplifier will be controlled very low amplitude signals from the antenna. For this purpose, it is mutual to see low noise field effect transistors used in these stages.
The ultrasonic amplifier is used to amplify the ultrasonic waves and the frequency range of these waves around 20 kHz to 100 kHz. They are used for particular purposes like ultrasonic cleaning, remote control systems, ultrasound scanning, etc. Each form will function at a narrow band of frequencies in the ultrasonic range.
Wideband amplifiers are used to amplify a band of frequencies. They amplify from DC to numerous tens of MHz They are used in apparatus like oscilloscopes, etc. These are used where there is a necessity to precisely measure signals over an extensive range of frequencies. Because of their extensive bandwidth, the gain is low.
The term DC amplifiers or Direct coupled amplifiers are used to amplify very low-frequency signals.The o/p of one stage is united with the input of the next stage in these types of amplifiers. This amplifier increases the DC frequency that is zero. They are frequently used in several electrical control and also measuring instruments.
Video amplifiers are used to increase the video signal and show it with high resolution.The video signal transmits all the information about radar systems and also picture on television. They are a special kind of wide band amplifier, used precisely for signals that are to be practical to video apparatus.
The video amplifier bandwidth depends on use. In television receivers, they spread from 0Hz-6MHz and is still broader in radar. These types of amplifiers are used to amplify the signals which are received from computer monitors, DVDs, and also to amplify the quality of the video in small TVs that are mounted in the vehicles.
Buffer amplifiers are normally used for electrical impedance conversion from one circuit to another. They have an amplifier gain of 1. They are used for separating the circuits from each other. They have a high impedance at the i/p and low impedance at the o/p.
Therefore can be used as an impedance matching device. This indicates that the signals are not reduced between circuits, which occurs when a circuit with high o/p impedance nourishes a signal straight to another circuit having a low i/p impedance.
Operational amplifiers or op-amp are high-gain electronic voltage amplifiers. These are used to achieve mathematical operations on voltages. They are used in the form of integrated circuits firstly, they were developed with the vacuum tubes. The Op-amp has two input terminals namely inverting and non-inverting. Operational amplifiers can be used as inverting amplifiers, summing amplifiers, non-inverting amplifiers, difference amplifier etc.
Thus, this is all about different types of amplifiers classified based on by their operation, characteristics or application. We hope that you have got a better understanding of this concept. Furthermore, any doubts regarding this concept or to implement electrical and electronic projects, please feel free to give your valuable suggestions by commenting in the comment section below. Here is a question for you, what is the function of an amplifier?