- #1
Aditya Mysore
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how do the appliances work with AC voltage when the polarity keeps changing?
How do the appliances work with AC voltage?
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SUMMARY
Appliances operate effectively with AC voltage due to their design, which does not require a specific polarity. In an AC cycle, the voltage and current alternate, but power remains positive throughout the cycle. Most appliances, such as TVs and computers, convert AC to various DC voltages for internal use. The ability to transform voltages efficiently using transformers is a significant advantage of AC power, enabling devices to operate on the required voltages without loss of power.
PREREQUISITES- Understanding of AC (Alternating Current) and DC (Direct Current) concepts
- Knowledge of electrical power calculations (Power = Voltage x Current)
- Familiarity with transformers and their function in voltage conversion
- Basic electronics knowledge regarding power supplies and voltage regulation
- Research the operation of transformers in AC voltage applications
- Learn about power supply design for converting AC to DC
- Explore the principles of voltage regulation in electronic circuits
- Investigate the differences between resistive and reactive loads in AC systems
Electrical engineers, electronics technicians, and anyone interested in understanding how appliances utilize AC voltage for efficient operation.
- #2
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Think of a resistance load. For the first half of an AC cycle voltage is plus and current is plus. Power is voltage times current, thus plus. In the second half of the cycle voltage is minus and current is minus, but voltage times current is still plus. (-1 * -1 = +1). So the directin of power flow is the same through the whole cycle.
- #3
- #4
davenn
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Aditya Mysore said:
primarily, because in general, AC appliances are not polarity conscious ... that is, they don't need a specific + and - supply like from a batteryDave
- #5
meBigGuy
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A light bulb does not care that the voltage is changing and polarity is reversing because it has a slow response time.
For systems that are sensitive, the AC is converted to DC. In fact, that is true for most appliances (other than toasters, heaters, AC motors, etc).
There is nothing in your TV that runs off the AC directly. It is converted to many different DC voltages. Same for your Computer.
For systems that are sensitive, the AC is converted to DC. In fact, that is true for most appliances (other than toasters, heaters, AC motors, etc).
There is nothing in your TV that runs off the AC directly. It is converted to many different DC voltages. Same for your Computer.
- #6
Aditya Mysore
- 6
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Then you mean to say the current keeps changing its direction?anorlunda said:
- #7
davenn
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Aditya Mysore said:
yes. that's its definition ... AC = Alternating Current
Dave
- #8
Aditya Mysore
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Well
That was my initial question.
Well then how can an appliance handle such kind of a thing when the current in the circuit keeps changing its direction?davenn said:yes. that's its definition ... AC = Alternating Current
Dave
That was my initial question.
- #9
meBigGuy
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Did you read my reply? #5
- #10
Aditya Mysore
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Yes I think you are right. Thanks :)meBigGuy said:
- #11
meBigGuy
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Aditya Mysore said:
It doesn't matter that I am right
, does it fully explain what you wanted to understand?In order to efficiently transform voltages you need AC power. The changing currents allow one to use transformers to efficiently change voltage without power loss. For example, 110VAC 0.1 Amp (11 watts) applied to a proper transformer would power a circuit that requires 5VAC 2.2A (also 11Watts). That ease of voltage transformation is one thing that make AC very useful. Then, after transforming voltage, there are very simple techniques to convert the AC to DC, which most electronic circuits require.
Your PC power supply (and most wall-wart chargers) do this to an extreme. They convert 110VAC/60Hz directly to DC and then chop it back into AC at high frequencies (100KHz or higher) to put it through a transformer that creates many AC output voltages. Then they convert those back to DC, say 5V, 12V, and 3.3V to power a PC. For various other reasons, creating 100KHz AC allows efficient power transfer through a cheaper, smaller transformer.
So, AC is not a problem for appliances, it actually makes it easy to transform the power to voltages needed by an electronic system. Most don't actually run on AC internally.