Power setting on hairdryers

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In summary, a hair dryer hooked up to a DC power supply has 2 power settings. One is 600 watts and the other is 1200 watts. The power settings are based on the resistance of the element in the hair dryer. If you have two resistors (24 ohms in this example) connected in parallel, you can create a power setting of 1200 watts.
  • #1
casanova2528
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A hair dryer hooked up to a DC power supply has 2 power settings.

One is 600 watts and the other is 1200 watts.

How is a hairsdryer able to have 2 power settings when resistance is constant and the voltage is constant?

Am I missing a valuable component inside a hairdryer that allows this to happen? What's going on?
 
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  • #2
The implementations I've seen are that the heating element is split into 2 parts.
In one mode only one section is powered in the other both sections are powered.
So the resistance in this case is not constant.
 
  • #3
so, with a higher resistance at constant voltage...the current must be lower. If current is lower at higher resistance, the power consumed is lower. so, at 600 watts setting, the hairdryer is connecting to the part that contains more resistance. IS THIS CORRECT?

it's a bit awkward because you would think that the higher resistance would produce a higher power setting.
 
  • #4
casanova2528 said:
so, with a higher resistance at constant voltage...the current must be lower. If current is lower at higher resistance, the power consumed is lower. so, at 600 watts setting, the hairdryer is connecting to the part that contains more resistance. IS THIS CORRECT?

it's a bit awkward because you would think that the higher resistance would produce a higher power setting.

Or they're two resistors connected in parallel?
 
  • #5
casanova2528 said:
A hair dryer hooked up to a DC power supply has 2 power settings.

One is 600 watts and the other is 1200 watts.

How is a hairsdryer able to have 2 power settings when resistance is constant and the voltage is constant?

Am I missing a valuable component inside a hairdryer that allows this to happen? What's going on?

What hair dryers are hooked up to a DC voltage source? That looks like a typo to me. Beyond that, the other replies are correct.
 
  • #6
berkeman said:
What hair dryers are hooked up to a DC voltage source? That looks like a typo to me. Beyond that, the other replies are correct.

this is a hypothetical situation...of course, AC voltage at 60 hz and peak voltage of 170 V is standard in the usa...but just to understand how a hairdryer power setting is setup...DC current is used.
 
  • #7
i'm not sure if that is correct...

look at your standard hairdryer with 2 power settings. the setting at higher power usually creates more heat for your hair drying purposes. the 600 watt setting should not create more heat, and the 1200 watt setting creates more heat. TRY IT YOURSELF...TURN ON A HAIRDRYER WITH 2 POWER SETTINGS...WHAT'S GOING ON?
 
  • #8
MATLABdude said:
Or they're two resistors connected in parallel?

casanova2528 said:
i'm not sure if that is correct...

look at your standard hairdryer with 2 power settings. the setting at higher power usually creates more heat for your hair drying purposes. the 600 watt setting should not create more heat, and the 1200 watt setting creates more heat. TRY IT YOURSELF...TURN ON A HAIRDRYER WITH 2 POWER SETTINGS...WHAT'S GOING ON?

Let's assume you have two resistors, both of resistance R (say, 24 ohms). On the low setting, only one of these resistors is connected:
[tex]P=\frac{V^{2}}{R}=\frac{120^{2}}{24}=600 W[/tex]

On the high setting, both of these resistors are connected in parallel, resulting in a total resistance of R/2 (in this example, 12 ohms). Consequently, the power consumed is:
[tex]P=\frac{V^{2}}{R}=\frac{120^{2}}{12}=1200 W[/tex]

It's because they are connected in parallel (and not series) that you can twice the resistance (if you just added up the numbers, ignoring their connectivity) and twice the power.
 
  • #9
oh...i haven't gotten to parallel and series resistors set ups.

so, if resistors are set up in parallel, you don't add the resistance like you add capacitance...is that right?
 
  • #10
casanova2528 said:
oh...i haven't gotten to parallel and series resistors set ups.

so, if resistors are set up in parallel, you don't add the resistance like you add capacitance...is that right?

:confused:How do you start connecting up capacitors before resistors?:confused:

But yes, you add them the opposite of how you add capacitances:
http://en.wikipedia.org/wiki/Series_and_parallel_circuits
 
  • #11
It could have a single element and an electronic (switched mode) power controller.

I seem to remember one which also altered the motor speed as well as the heating power.
 

1. What is the purpose of different power settings on hairdryers?

The different power settings on hairdryers allow users to adjust the speed and intensity of the airflow. This can be useful for different hair types and styles, as well as for controlling the level of heat applied to the hair.

2. How do I know which power setting is best for my hair?

It is best to start with the lowest power setting and gradually increase it until you find a level that dries your hair efficiently without causing damage. Fine or thin hair may require a lower power setting, while thick or curly hair may need a higher setting.

3. Can using a higher power setting on a hairdryer damage my hair?

Using a higher power setting on a hairdryer can potentially damage hair if it is used too close to the scalp or if the heat is too intense. It is important to use caution and not hold the dryer too close to the hair or use it for extended periods of time.

4. Are there any benefits to using a lower power setting on a hairdryer?

Using a lower power setting on a hairdryer can be beneficial for those with fine or damaged hair. It can also help to reduce frizz and prevent heat damage. Additionally, using a lower power setting can save energy and prolong the lifespan of the hairdryer.

5. Can I switch between power settings while using a hairdryer?

Yes, you can switch between power settings while using a hairdryer. However, it is important to avoid constantly switching back and forth as this can put strain on the motor and potentially damage the hairdryer. It is best to find the appropriate power setting for your hair and stick with it for the duration of your blow-drying session.

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