What is the Difference Between AC and DC
Length: 729 words (2.1 double-spaced pages)
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First off, what is current. Current is expressed in a unit called Amps. Amps are a measurement of how many electrons pass per second. That is to say, a wire with 40 coulombs passing any point in a 2 seconds would be said to have 20 Amps of current (40 Coulombs (a unit of charge given as 6.24x1018 electrons) / time in seconds or in this case, 2 seconds. The Amp is also known as Coulombs per second) Another trick about current is that it is measured in the movement of the positive charge. Literally that is to say the current moves in oppostion to the electrons. This is because originally it was thought that the positive charge is what moved, both are viable, but in reality a positive charge is generally fixed since within an atom the electrons are migratory, while the protons and neutrons tend to be stationary.
What is AC/DC?
AC and DC literally stand for Alternating Current and Direct Current. Direct Current is very convenient and is used in many modern day utilities. For a circuit with DC the current is constanly in one direction, while the voltage remains constant. This makes for a simplistic circuit, for example a flashlight, The batteries are a source of electrochemical DC power and . However AC is called Alternating Current because the voltage changes from negative to positive a given number of times a second, this is also described as the frequency of the power. An example of this would be a motor ran by a hand crank. The inversing of charges creates a sinusoidal graph which looks something like figure 1 (given in radians). This makes for an unsteady power source and can often times be warped from the sinusoidal shape. So the main difference between AC and DC is the way the energy is transmitted.
Why are we using Alternationg Current today? There are a few reason although mainly it was due to the technology of the late 1800's and early 1900's. Nikola Tesla being one of the leading scientists for Alternating Current, created a way to run engines and also convert AC Volts and Amps. He came up with this while he was supposedly in a park in Budhapest. He sat down and drew out the basic diagram of a motor run by a magnetic flux.
This supplied Alternating Current with a serious advantage. The loss of power per mile tramitted is proportional to that of the Current squared. If Tesla was able to convert the Amps to Volts, then they could easily have a place where the power is upped to a high amount of volts for transfer, and then lower the volts at the other end to a more acceptable value. This however had not been developed for DC, which was supported by the renowned brain-box Einstein. Unfortunately Einstein attacked AC by trying to prove that a high voltage was seriously deadly. As it turns out this however true was not proper, amps can kill much more efficiently than volts. Unfortuantely for the proprietors of DC they were forced to supply their power at a high amperage and a low voltage, which specifically has a high loss of power over shorter distances. This was one of the main clinching facts for the use of AC over DC.
Advantages to AC
In the early 1900's Ac certainly had an advantage, although many have been reduced there are still some properties unique to each current:
# Thanks to the invention of the Transformer by Tesla, AC power was capable of traveling at high voltages and low amps, decreasing the loss of power significantly, however more recently a way to step up and down DC power has given DC power a chance once again.
# AC power inverts it's polarity at a controllable interval.
# AC power is more simplistically created from mechanical energy
# AC power can instigate a constant magnetic flux such as what is called an electromagnet.
# Used in nearly all 1st world countries as main power source.
# Can seperate current and voltage for complex circuits.
Advantages to DC
# DC circuits are simplistic and used in many household devices
# Generated chemically, such as with alkaline batteried or hydrogen fuel cells
# Constant energy source
# Generally no electromagnetic flux
# Can be stepped up and down in voltage
# Low to no impedence
# Current and Voltage are always in Phase