How Does a Hairdryer Use Less Current Despite High Home Voltage?

  • Context: Undergrad 
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    Electricity
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SUMMARY

The discussion clarifies how electrical appliances, such as hairdryers, operate within a home electrical system that supplies 230 volts at 13 amps. The key point is that the amp rating of a circuit indicates its capacity, while the appliance itself draws only the current it requires, determined by its internal resistance. This relationship is analogous to water flow, where voltage represents pressure and current can be adjusted by resistance, similar to regulating a faucet.

PREREQUISITES
  • Basic understanding of electrical concepts, including voltage and current.
  • Familiarity with Ohm's Law, which relates voltage, current, and resistance.
  • Knowledge of electrical circuit ratings and fuse functions.
  • Concept of resistance in electrical devices.
NEXT STEPS
  • Research Ohm's Law and its applications in electrical circuits.
  • Learn about the function and importance of fuses in electrical safety.
  • Explore the relationship between voltage, current, and resistance in various appliances.
  • Investigate how different appliances manage electrical loads and their design considerations.
USEFUL FOR

This discussion is beneficial for parents, educators, and anyone seeking to understand basic electrical principles and how household appliances function within an electrical system.

ethan12
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Hi,
The UK., electricity supply is 13 amps at 230 volts. With such a current and e.m.f., how can we run appliances which don't need that e.g., a hairdryer with a 3 amp fuse. What stops the full 13 amps overwhelming the appliance? My question is not well put but I'm sure you know what I'm getting at. I'm a parent trying to help my son and I would like to give him the right answer even if the answer might take some thinking about. It's not for his homework just for our understanding.
Thank you for reading this.
Regards,
Ethan12.
 
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Welcome to PF. The amp rating of a circuit is just a capacity. The electrical device draws whatever amperage it needs.
 
For a given amount of voltage, the current goes down as the resistance goes up, and the hair dryer has a certain amount of resistance in it.

You can think of similar situation with a water faucet. The pressure of the water is the voltage, and you can regulate the current by opening or closing the faucet.

I don't know much about electricity and I'm kind of talking out of my *** and/or oversimplifying it, so someone correct me if they can.
 

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