Types and Quality of Amplifiers - Coursework Example

Amplifiers Introduction An amplifier can be described as a device that is used to increase thepower of any signal through the use of an external source of energy (York 12). There are various types of amplifiers that can be found today with different purposes. The amplifiers can be classified in various ways resulting from the ways they are applied, the frequency range that the amplifiers cover and in other cases, the active devices that are used. In terms of usage, it is expected that the amplifier will be basically increasing the power of the said signal without doing any sort of alteration on it. Therefore, practical amplifiers will have finite distortion and minimal noise with which they will invariably add to the said signal (Bishop 98). An exception is given to the cases where the amplifier is a transducer, which means that the amplifier shifts the types of signals from one point to another. Types of Amplifiers The mainstay of any electronic circuit will certainly be the amplifier (Bishop 18). Classification of amplifiers is broad, but the best way in which amplifiers can be classified is in relation to the input and output of each amplifier. In order for the amplifier to have some gain, it means that the scale of the input and output signal to the amplifier will have some degree of variation. The definition of it can be summarized as the quotient of three aspects, i.e., the power, the current and also the voltage. Furthermore, the gain will also be in terms of the output or the input signals of either the voltage or the power in any amplifier (Satyam and Ramkumar 32). In cases where the gain is undefined, it implies that the input and the output signals in an amplifier are almost the same in terms of unit signals; thus, in most cases a good example will be the decibel which has the same format described. This is not the case on a usual basis as there are other cases of amplifiers that do not follow this procedure like the transconductance amplifier. For the gain to occur in an amplifier, many dynamics will have to be given special attention. These dynamics that will have to be put into consideration as an amplifier will include aspects such as the power source for the amplifier, the impedance on load in relation to the said amplifier and also the amount of the voltage going through the amplifier (Bishop 33). Some other amplifiers that cover all these aspects will have the impedance meant specifically for the transfer of power within the amplifier. Driven by the desire to have a high quality result, amplifiers will have their impedance used together as output and input signals in the amplifier. Most researches indicate that the best way to effectively use an amplifier will be having the input and output circuits placed in a linear manner. This will enable the amplifier to have a constant gain while it is being in use. York asserts that the inconsistency of the gain in an amplifier will imply that the resultant signal is always altered, thus meaning that the resultant effect will be very poor quality (56). This sometimes is not the case in other amplifiers that find the variation and the inconsistency of the signals very useful. The most common types of amplifiers are the electronic ones, and with electronic amplifiers there are different and unique types underlying the common electronic amplifiers. Case in point are the electrical amplifiers that can be found in the household appliances such as the vacuum cleaner, and also in other home appliances such as stereo and television systems. In order to get different types of amplifiers that use the electronic circuit, below are a few examples. Power Amplifier When it comes to power amplifiers, there have been different descriptions with each of the description having relevance to the way that a power amplifier can be used, or the purpose of the usage. In one instance, the amount of energy is the most crucial aspect in the power amplifier as it will be the determining factor when it comes to the comparison with the power supplied to the circuit, according to Kal (23). In transmission of a signal from the time there is the input signal to the output signal in a circuit, the power amplifier will always be the final amplifier in the process, and this is so since the power amplifier will enable consideration to be put in the maximum usage of power in the whole amplifier system. Because of the maximum usage of power in the whole system, it has brought about different categories of amplifiers on that basis. There are other power amplifiers that are based solely on the output of transistors. In other samples of power amplifiers, there are ones classified in relation to the way the amplifier is applied in usage, and at the same time other amplifiers will not pay any special attention to the linearity of how the sequences have been placed. Circuits of the Power Amplifiers With the power amplifier, circuits are broadly classified into two categories. One category includes the valve amplifier which in many cases is mostly effective in usage for military equipment such as countermeasures, and also in hi-tech communication systems in the military. One area that is common for their usage is their very good quality of sounds, hence the reason why it is mostly used by various military outfits in the world. The second type of the power amplifier circuit includes the circuits based on their output which is mostly single ended. The second category is the least common in terms of its usage and thus, very few information is available on its usage and cases where it is highly effective. Transistor Amplifier Many researchers argue that the transistor amplifier is very crucial in an amplifier system. This is because of the role it plays in the signal relayed through it. One of the important functions it performs is that it helps in the magnification of any signal input through the amplifier and the result is that a higher output signal will be released from the amplifier. This magnification of the transistor amplifier has factors, too, which will be put into consideration, enabling it to have a higher magnification trend. One of the factors that help in the amount of magnification relayed by the transistor amplifier is the intention of the circuit in the external amplifier; this is done so in order to check whether it is compatible with the device that is active and helps in the relay of output signals. One of the areas that actively uses the transistor amplifier are the speakers at home in the stereo. This is a good example of an area where the transistor amplifier is actively applied in its usage as the input signal in the stereo will end up being magnified greatly in the output signal, which in this case will be the speakers relaying the sound that can be increased or decreased at will. The amplifier that is transistor based will mostly have various configurations depending on the system. A point to note is that each configuration will have different characteristics in relation to the gain and impedance among other characteristics. Other forms of amplifiers will include operational amplifiers, fully differential amplifiers, video amplifiers, oscilloscope vertical amplifiers, distributed amplifiers, switched mode amplifiers, etc. The Amplifier Quality There are different classes of amplifiers that are categorized according to their eminence. Some of the features that classify amplifiers under this category include: The Amplifier Gain It is referred to as the quotient of the power and the SI unit of the gain is the decibel (Jung 26). The gain will be the specification of most of the amplifiers in the sense that the relation between the voltage, power and impedance has to be present in order for a significant gain to be seen in an amplifier with each amplifier having a varying gain as compared to another amplifier. When two amplifiers equivalent to one another are compared, one that has more reception with relatively a higher gain will have a minimal input and the resultant effect will be a specified power output. Amplifier Bandwidth Bandwidth is described as the level or amount of frequencies with which the amplifier has the capability of amplifying at its most effective position (York 77). The amplifiers should ideally be with a bandwidth that has frequencies in the range that the amplifier is intended to amplify. If the bandwidth is too tapered, the signals will be lost in the said frequencies, and also when the bandwidth is too wide, the signals will be interfered with, and hence unwanted signals in the bandwidth. In the case of the tapered bandwidth, the signal can have a hum which is associated with low frequency, while a too wide bandwidth will have a hiss which is brought about by high frequency. Efficiency of the Amplifier This is the extent to which the source of energy has been quite effective to the amplifier in relation to the output from it. In order to be efficient, efficiency will range from 10 percent to 20 percent, with a maximum efficiency of up to 25 percent of the output from the amplifier. This will imply that the amplifier belongs to class A. Bishop asserts that class B amplifiers in most cases have a high efficiency rate but on their own, they are quite ineffective for audio work as they have a high level of distortion (88). Other factors that affect the quality of amplifier will include linearity where the amplifiers to be effective have to be linear in order for them to be ideal. Also, noise is quite important as the amount of noise emitted during the amplification process determines the quality of the amplifier. Another factor to be put into consideration should be the output dynamic range, the slew rate and also the rise time on the amplifier. Works Cited Bishop, Owen. Understand Amplifiers. Oxford, England: Newnes, 1998. Web. Jung, Walter G. Op Amp Applications Handbook. Burlington, MA: Newnes, 2006. Web. Kal, Santiram. Basic Electronics: Devices, Circuits and It Fundamentals. New Delhi: Prentice-Hall of India, 2003. Print. Satyam, M, and M. Ramkumar. Foundations of Electronic Devices. New York: J. Wiley, 1990. Print. York, H. Lewis. Amplifiers. New York: Focal Press. 1964. Print. Read More