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# What is electricity How does it work Nikola Tesla’s AC vs DC

What is electricity How does it work Nikola Tesla’s AC vs DC

Tesla imagined impossible technologies more than a hundred years ago. He and Thomas Edison have arguably had more of an impact on modern technology than any other scientists.

Tesla’s biggest contribution may be his innovations in alternating current technology, and the invention of the AC motor. The adoption of this technology was not easy because Thomas Edison’s direct current systems had been the standard early on. What is AC and DC, and why is one superior to the other?

Atoms have a positively charged nucleus and negatively charged electrons surrounding the nucleus. But electrons in the outermost shell of the atom, called the valence shell, can sometime become free due to external forces. These electrons can move from one atom to another. This is what can cause a movement of charge, which is what electricity is. An electrical current is the flow of free electrons from one atom to another.

The relationship between current, voltage, and resistance is described by Ohm’s law, Voltage = Current x Resistance. Current (amps) is the rate at which the charges flow. It is analogous to the rate of flow of the water in a hose. Voltage (volts) is the force required to make current flow. It is analogous to the water pressure in a hose. Resistance (ohms) is a material’s tendency to resist the flow of charge. This is like diameter of the hose. The smaller the hose, the higher the resistance.

DC is similar to the normal flow of water through the hose that we see. The water flows in one direction. AC is like the water flowing back and forth within the hose 50 or 60 times per second, 50 Hertz or 60 Hertz. This is where the water analogy is not so great, because water doesn’t flow back and forth in a hose.

AC won over DC because of efficiency and power delivery. Power is like the volume of water coming out of the hose.