Why do all electronics such as laptops Use DC power when The Electricity our House Runs on is AC?
And Whats the Difference between AC And DC? I know that "AC" is Alternating Current and "DC" is Direct current But what are they and why do we convert them between each other...
And Whats the Difference between AC And DC? I know that "AC" is Alternating Current and "DC" is Direct current But what are they and why do we convert them between each other...
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That is a very good question!
First, DC (direct current), such as from a battery, doesn't change polarity. The positive terminal of a battery is always positive. Alternating current on the other hand, alternates between positive and negative cycles at regular intervals. In the U.S., AC power changes polarity 60 times per second.
So why AC? AC, unlike DC can be stepped up and stepped down to very high or low voltages very simply. It is useful to step up AC power to several hundred kilovolts for transmission lines (see Ohm's Law), then step it down to an intermediate voltage (about 2200 volts, AC) for regional distribution, then to 120 volts AC for delivery into your home. If you've ever noticed those large, gray cans on the utility poles, those are step-down transformers to drop the 2200 or so volts to 120 volts for your home.
Okay, so why is AC delivered to your home? There are many devices in your home that require AC power to operate: your refrigerator, air conditioner, washing machine, furnace blower, dishwasher, hair dryer, clothes dryer . . .anything that has a motor.
So, what about consumer electronics? Each unit has a built-in power supply that steps 120 volts AC down to the required voltage, rectifies the power (converts AC to DC), filters (smooths) the rectified DC, then regulates it for use by the electronic circuits in your computer, flat screen tv, etc. Typically, high-power appliances are AC operated, while lower power, consumer electronics operate on DC (derived from 120 volts, AC).
A bit of history: DC cannot be transmitted any appreciable distance without significant losses. Thomas Edison who championed DC electric power discovered this, but fought to electrify America with DC. George Westinghouse appeared on the scene, promoting AC power to light and power America. This was not Westinghouse's brainchild, but rather that of a brilliant Croatian immigrant: Nikola Tesla. George Westinghouse simply sponsored Tesla's idea of AC power. Today, we have Nikola Tesla to thank for the ease with which we receive our AC power reliably and economically.
First, DC (direct current), such as from a battery, doesn't change polarity. The positive terminal of a battery is always positive. Alternating current on the other hand, alternates between positive and negative cycles at regular intervals. In the U.S., AC power changes polarity 60 times per second.
So why AC? AC, unlike DC can be stepped up and stepped down to very high or low voltages very simply. It is useful to step up AC power to several hundred kilovolts for transmission lines (see Ohm's Law), then step it down to an intermediate voltage (about 2200 volts, AC) for regional distribution, then to 120 volts AC for delivery into your home. If you've ever noticed those large, gray cans on the utility poles, those are step-down transformers to drop the 2200 or so volts to 120 volts for your home.
Okay, so why is AC delivered to your home? There are many devices in your home that require AC power to operate: your refrigerator, air conditioner, washing machine, furnace blower, dishwasher, hair dryer, clothes dryer . . .anything that has a motor.
So, what about consumer electronics? Each unit has a built-in power supply that steps 120 volts AC down to the required voltage, rectifies the power (converts AC to DC), filters (smooths) the rectified DC, then regulates it for use by the electronic circuits in your computer, flat screen tv, etc. Typically, high-power appliances are AC operated, while lower power, consumer electronics operate on DC (derived from 120 volts, AC).
A bit of history: DC cannot be transmitted any appreciable distance without significant losses. Thomas Edison who championed DC electric power discovered this, but fought to electrify America with DC. George Westinghouse appeared on the scene, promoting AC power to light and power America. This was not Westinghouse's brainchild, but rather that of a brilliant Croatian immigrant: Nikola Tesla. George Westinghouse simply sponsored Tesla's idea of AC power. Today, we have Nikola Tesla to thank for the ease with which we receive our AC power reliably and economically.