Alternating Current v/s Direct Current

A rather simple topic!

WHAT?
       There are mainly two types of electricity in this world, namely Alternating Current (AC) & Direct Current (DC). But before that what is current? In theory, it's just a flow of electron, but in a practical scenario I've seen anything like that, what I felt is a torturing heat, and that's because of a higher CURRENT!. The supply we get in our house, industry, college almost everywhere is Alternating Current. Its produced from hydroelectric generators here, mainly. 'AC' man is seen as something like this when plotted in a graph.

Mr. Alternating Current

         Once again Mr. Faraday came into our context. According to his law of electromagnetism predicts how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF). Consider a magnet with its south and north poles separated in space and when a coil rotates in between this poles, electricity will be produced in the terminals of the coil. (Simple as when you pedal a cycle, the dynamo produces a voltage which runs the headlamp in an alternating way). This is the basic working of a generator. If you put your head up a bit more, you can find how it got its name alternating. Since the coil is cycling between the poles the electricity produced varies from a maximum to zero to minimum. And that's the reason its AC.

          

Thomas Edison

Nikola Tesla

                                  

        But this 'DC' man is decent, he doesn't wobble around but makes his position constant throughout the time. And simply called Direct Current. This can be harvested by the newer technologies such as solar, our home utility batteries, and a bit complex AC to DC rectifiers and all. Let's not make this complex. So, a remote battery produces DC, Solar cells produce DC, but our power sockets produce AC, A simple motor produces AC.

Mr. Direct Current

                             

   Once there was a tight discussion on what supply would be used for the transmission. Mr. Thomas Edison, he always looked into business and he stated the transmission of DC supply would be economical. The remuneration from the companies begun as a problem when the company asks him to find a better solution then to transmit DC. In this scenario, he asked Mr. Nikola Tesla to find a better solution, who was also a student of Edison. Mr. Tesla found that AC can be transmitted over long distance without much power losses but when he put this idea, Edison try to oppose Tesla because the remuneration would have been given to Tesla. Edison even tried to show that AC transmission is dangerous by electrocuting elephant and other animals. Even though the company was so much satisfied with Tesla's AC transmission and signed an agreement with Tesla

FREQUENCY

     That'sats enough for basics torture.. Now practically speaking DC has zero or no frequency and it's much safer as compared to AC (Still dangerous at a higher voltage). But our AC is simply deadly killer :) DO NOT TOUCH IT!. Once you touch it, whatever kind you may be, you'll make the tortured sound (if you don't make it either you are hobbyist with AC or you are dead, kidding!).

Ways of electric shock 

         I've seen many youtube videos and searched on google for frequency vs pain. The interesting facts are that DC is much safer to be barely touched with your hands up to 60-70 volts, but with the same condition, it hurts a lot for AC even at 12 volts. (Thanks to Great Scott and Electro Boom youtube channels). In one of their tests its seen that with increasing frequency, pain by AC increases. And deeper searches showed me that most of our heart and neuro functions are based on 50-100Hzthat'ss the reason you get a severe shock when touching our city supply which has a 50-60Hz frequency. And the other reason why we get hurt is that the human body has a parasitic capacitance (capacitance which our has with our surroundings) which combines with our body resistance forms a complex impedance which increases the current flowing through our body, A SHOCK!

Shock !!

WHY?

           The AC is mainly used because of the transmission, Mr. Tesla was so genius that he showed how, for the same power, AC is well suited as it dissipates fewer losses as compared to DC. Another important advantage was how easy it is to be produced than DC, mainly due to the lack of extra physical components needed for DC generation. Its also because three-phase AC can deliver larger loads to the industries where is needed. For DC transmission with lower voltage, for the same load, DC transmission would have to pass higher currents which in return increase the conductor size which increases the conductor cost dramatically.

ADVANCEMENTS

             Apart from all these mankind achievements, many more advancements are there in the field of power generation. Like HVDC (where higher volt DC, around 800kV transmission have been experimenting),  as part of this advancement, India is going to launch its 800kv HVDC in AP on 31st of April, advanced storage methods (Sodium batteries), higher capacity Li-ion batteries

  Not just a simple topic !!