DC is defined as the "unidirectional" flow of current; current only flows in one direction. Voltage and current can vary over time so long as the direction of flow does not change. To simplify things, we will assume that voltage is a constant. For example, we assume that a AA battery provides 1. What does this mean? It means that we can count on most DC sources to provide a constant voltage over time. In reality, a battery will slowly lose its charge, meaning that the voltage will drop as the battery is used.
For most purposes, we can assume that the voltage is constant. Almost all electronics projects and parts for sale on SparkFun run on DC. Examples of DC electronics include:. Almost every home and business is wired for AC. However, this was not an overnight decision. In the late s, a variety of inventions across the United States and Europe led to a full-scale battle between alternating current and direct current distribution.
Thomas Edison, on the other hand, had constructed DC power stations in the United States by A turning point in the battle came when George Westinghouse, a famous industrialist from Pittsburgh, purchased Nikola Tesla's patents for AC motors and transmission the next year.
Thomas Edison Image courtesy of biography. In the late s, DC could not be easily converted to high voltages. As a result, Edison proposed a system of small, local power plants that would power individual neighborhoods or city sections. Even though the voltage drop across the power lines was accounted for, power plants needed to be located within 1 mile of the end user. This limitation made power distribution in rural areas extremely difficult, if not impossible.
With Tesla's patents, Westinghouse worked to perfect the AC distribution system. Transformers provided an inexpensive method to step up the voltage of AC to several thousand volts and back down to usable levels.
At higher voltages, the same power could be transmitted at much lower current, which meant less power lost due to resistance in the wires. As a result, large power plants could be located many miles away and service a greater number of people and buildings.
Over the next few years, Edison ran a campaign to highly discourage the use of AC in the United States, which included lobbying state legislatures and spreading disinformation about AC. Edison also directed several technicians to publicly electrocute animals with AC in an attempt to show that AC was more dangerous than DC. In attempt to display these dangers, Harold P. In , the International Electro-Technical Exhibition was held in Frankfurt, Germany and displayed the first long distance transmission of three-phase AC, which powered lights and motors at the exhibition.
Several representatives from what would become General Electric were present and were subsequently impressed by the display. The following year, General Electric formed and began to invest in AC technology. Westinghouse won a contract in to build a hydroelectric dam to harness the power of Niagara falls and transmit AC to Buffalo, NY.
The project was completed on November 16, and AC power began to power industries in Buffalo. This milestone marked the decline of DC in the United States. Who invented Alternating current? What are the applications of alternating current?
Alternating current is mainly used in the industry of the transportation and production of electricity. Skip to main content. Your health and safety are our highest priority during this time.
Click here for our precautionary measures. AC Your home or office receives electricity in the form of wave-like AC current, which is capable of changing direction and voltage from higher to lower current with the aid of transformers. DC The consistent and constant voltage of DC power supplies electronics that use a battery, such as your mobile device or smartphone.
Aug 7, Explanation: Alternating current is used in most electricity distribution systems for several reasons, but the most important one is the ease with which it can be transformed from one voltage to another. All "room temperature" conductors have resistance, so they heat up when carrying current. Other reasons are: DC is more lethal than AC for the same voltage because it's harder to let go of if touched as the voltage does not go through zero. Muscles contract with constant force with DC.
Electrolytic corrosion is more problematic with DC. DC arcs do not "quench" as easily because voltage does not go through zero. AC induction motors are simple to make and maintain.
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