Alternating Current and Direct Current - Essay Example

?Client’s 22 July There are two main specific types of currents and they are alternative current and direct current, the directionof the current flow is altered or reversed in the case of alternative current, this alteration is done on a regular basis. Direct current is a little different from alternative current because it flows in the same direction all the time and no alteration is done with it like in the case of alternative current. This paper will comprehensively discriminate between alternative current and direct current, major differences will be highlighted and a conclusion will be presented at the end of the paper. Alternative current won over direct current in the 20th century when it was chosen over DC because people considered it more reliable, it had very few risks and this is why it was chosen as the standard current in North America, DC on the other hand had several major issues which were later sorted out and fixed. After fixing the major issues with DC several European countries chose it as their standard current, these days DC is being used in some of the elite European countries. It is necessary to have a circuit in order to distribute electricity. A circuit is usually made up of two wires which lead up to a device which uses electricity. In the case of alternating current, one of the two wires is positive and the other is either neutral which is also known as ground or negative, the two wires take their turns which enables sending electricity. In direct current the process works a little differently, the polarity in DC is always the same unlike in the case of AC where in polarity differs, in a DC circuit one wire is negative which means the other is sending electricity and is positive, the negative wire does not send electricity in a DC circuit. There is no cyclic change and hence no hum in a DC, it is a fact that DC scores over AC in long-distances. In high-voltage transmission also DC is preferred because in AC a lot of electricity is lost, in DC less wastage takes place and this is why it scores over AC. AC scores over DC when it comes to converting DC into AC, it takes a lot of money to do that and it is not advisable to do so. DC should ideally be used only for long-distance transmission and AC in all other circumstances. Heating elements and light bulbs hardly care if the electricity supplied to them is DC or AC but it is very important to note that most modern day electrical gadgets require DC to work effectively. These days a transformer is used which consistently converts AC into DC for the devices to work effectively. In countries like Canada and the United States AC outlets have a voltage of 115 V and this is at 60 Hz. In European countries this is much different; most countries use 220 to 240 V which is about 50 Hz. It is also important to understand how peak voltage works, 115 V AC power usually has a peak voltage which is in the region of 163 V. Home and office electrical outlets are delivered electricity when the terminal has one hot and one neutral terminal. AC voltage is preferred by several people because a transformer is used to convert it into DC and it is very easy and a reliable source of getting direct current. A transformer consists of two inductors, the loops and turns present in these inductors are very different from each other. The number of turns usually determines the ratio of primary to secondary voltage. Electric generators have been made to produce alternating current, they can also produce DC but this can only be done by using a rectifier. A rectifier is made up of diodes which are also the most important part of a rectifier; the main use of a diode is that it allows the current to flow only in a single direction. DC power can also be converted into AC power; this can be done by using an inverter. Heating and arcing are two problems which are involved in producing AC and DC, alternating current can be generated at a much higher voltage than DC and the best part is that there will be fewer problems like heating and arcing. It is also important to note some of the standard values of voltage they are as follows: 2300 4600 6900 13,800 33,100 All these are in volts and these are the standard values when it comes to voltage, a significant increase in these values take place and as a result we get 100,000, 200,000 and 800,000 these are converted to transfer over long distances. The voltage is significantly decreased at the load are, it is reduced to 120,208,240, 277, 440, 480, 500 all the values are again in volts. AC can significantly ease the work load of raising and lowering voltage, this is why it is considered ideal. Another advantage of AC is that it can easily produce a magnetic field which varies. This changing field is then utilized to lower and raise the voltage, when transformers are used by lighting units the results become better and almost immaculate. Induction motors are also very useful; these motors use transformers in their operation and are reasonably priced. They occupy very little space when compared to a DC motor. DC motors score over AC motors when it comes to speed control, the DC motor has a much better speed control feature than the AC motor and this is perhaps its biggest advantage over AC motor. The following part of the paper will comprehensively analyze the advantages of DC power over AC power. Resistance: The amount of resistance is reduced by the DC system something which the AC system fails to do. Reactance: No reactance is introduced in the line in a DC system much different from an AC system. Frequency: No synchronization is required in a DC system because there is no frequency to monitor since the frequency is zero. Power: The real component is nothing but power in a DC system. Analysis: DC system deals mainly with real numbers hence the analysis is very easy, on the other hand the AC system makes use of complex numbers resulting in a complex analysis. Susceptibility: The effect of charging current is removed in a DC system, it does not introduce any kind of susceptance. No Inductance: Absence of inductance on a DC system helps regulate the voltage better, in an AC system it is very hard to do the same. Conductors: An AC system requires 3 conductors on the other hand a DC system requires only 2 conductors again scoring over an AC system. Skin Effect: An entire cross section area can be used in a DC because it leaves no skin effect but the same cannot be done in an AC. Insulation: A DC system requires lesser insulation than an AC system. Capacitance: Less power loss in a DC system is the result of complete absence of capacitance. The same is not the case in an AC system. The only con which prevents the DC from being used very widely is its incapability of transforming voltage into different levels. If the DC system was capable of the same then it would become the preferred system because it is much more efficient then the AC system, when it comes to monitoring, it is easier to monitor than the AC system. When it comes to analyzing, a DC system is much easier to analyze than an AC system because it makes use of real numbers as mentioned earlier in the paper. It is also important to note the three different steps involved in transforming DC voltage. The following are the three most important steps: Rectification from AC to DC Transformation from AC to AC Conversion from DC to AC These were some of the biggest advantages of using a DC system; it scores over an AC system in so many ways but its inability to transform voltage into different levels is its biggest lag and because of which it is not widely used. (Direct and Alternating Current) “The other key characteristic of AC is its frequency, measured in cycles per second (cps) or, more commonly, Hertz (Hz). This number describes how many times in a second the voltage alternates from positive to negative and back again, completing one cycle. In North America, the standard is 60 Hz, meaning 60 cycles from positive to negative and back again in one second. In other parts of the world the standard is 50 Hz.” (Direct and Alternating Current) Above is a diagram which sheds light upon the different voltages used in different countries, as mentioned earlier in the paper the North Americans use AC and DC, is widely used in Europe. “One might wonder why anyone would bother with such a thing as AC. It is true that in some cases AC holds no practical advantage over DC. In applications where electricity is used to dissipate energy in the form of heat, the polarity or direction of current is irrelevant, so long as there is enough voltage and current to the load to produce the desired heat (power dissipation).” (What is Alternating Current?) The polarity of AC and DC varies and the same is being talked about in the paragraph above. The inability if DC has been highlighted over and over again. “The difference between alternating current (AC) and direct current (DC) is really as simple as their titles suggest. Direct current is steady and flows in one direction (hence, it flows directly) while alternating current rises and falls as it continually changes direction (hence, it alternates). They are both essentially the same thing; a flow of electrons. However there are fundamental differences between them and these differences can be found in two places how the electricity is generated, and how it is used.” (Alternating Current) The conventional power plants successfully produce AC and the same is being transferred to the houses of people, there is a simple logic behind this, time and again it has been highlighted in the paper that AC is produced quite easily when compared to DC and devices are later used to convert AC into DC. Hydro power, coal turbines and wind turbines are places where AC is produced; it is produced there because all these involve moving parts. Power transmission mainly uses AC current, modern day electronic devices come equipped with converters which instantly convert AC current into DC current because these electronic devices require DC current to function effectively as discussed earlier in this paper. Conclusion “One advantage of alternating current is that it is relatively cheap to change the voltage of the current. Furthermore, the inevitable loss of energy that occurs when current is carried over long distances is far smaller with alternating current than with direct current.” (Alternating Current and Direct Current) The paper shed light upon several advantages and disadvantages of both DC and AC, how AC is converted into DC has also been discussed in this paper. A comprehensive list of the advantages of DC over AC has been presented in this paper. It is important to note that DC is easier to analyze and has a plethora of other advantages but DC’s inability to convert different voltages is a big con because of which AC is used more widely then DC. However, the modern day electricity devices require DC so they come with automatic converters that instantly convert AC into DC. For transferring current over a long-distance DC is used because it is cost-effective but otherwise AC is used, another difference is that people in North America use AC and people in European counties use DC. These were some of the advantages, disadvantages and the most important differences between alternative current and direct current. Works Cited Alternating Current and Direct Current. Similar Terms. n.p., Web. 22 July. 2011. Alternating Current. A Simple Explanation. n.p., Web. 22 July. 2011. “Direct and Alternating Current.” Electrical Power Basics. n.p., Web. 22 July. 2011. “What is Alternating Current?” Direct Vs Alternating Current. n.p., Web. 22 July. 2011. Read More