Does a photo-resistor create an AC current?

In summary: This is not what the OP wanted to know. What he was asking is whether there is an AC current that can be produced with a frequency similar to the light hitting a photoresistor. Yes, a radio transmitter does that. Just put your magnet next to a cell phone while talking. What effects would you see? Probably nothing.
  • #1
grahas
32
1
I'm a high school physics student. I want to do an experiment to see what happens when a high frequency alternating current goes through a magnet. To create the high frequency alternating current could a photo resistor do that for me? Does the photo-resistor create an alternating current with a frequency equal to the light hitting it?
 
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  • #2
No, a photoresistor can only change the value of its resistance depending on the light level, and the frequency of the light doesn't produce an alternating effect.

You could vary between lower current and higher current with a photo resistor and a battery, but that's not exactly what you're asking for (the current would never go negative). Furthermore, I don't even think photoresistors respond quickly enough to alternate the current at even moderate frequencies.
 
  • #3
Is there any way to achieve an alternating current with a frequency in the range of light, via a mechanical or electrical device?
 
  • #4
Not to my knowledge. The frequency of light is much, much bigger than, say, microwave frequencies.
 
  • #5
Well, I'll post back the results of my experiment to close the thread, thanks for the help!
 
  • #6
grahas said:
I'm a high school physics student. I want to do an experiment to see what happens when a high frequency alternating current goes through a magnet

Are you saying you want to use the magnet as a conductor? I don't think anything is going to happen. What would you like to see happen?

As for high frequency AC, your wifi network runs at 2.4GHz. Low frequency (red) light is 400,000 GHz.
http://www.laserfocusworld.com/articles/print/volume-49/issue-07/newsbreaks/world-s-fastest-photodetector-has-70-ghz-bandwidth.html
Photodetectors respond to the amplitude of the light, not the light frequency

Nothing electrical directly responds at the frequency of light.
 
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  • #7
meBigGuy said:
Are you saying you want to use the magnet as a conductor? I don't think anything is going to happen. What would you like to see happen?

other than short circuiting the power supply :wink:

to the OP ... definitely not a wise thing to do
 
  • #8
grahas said:
Is there any way to achieve an alternating current with a frequency in the range of light, via a mechanical or electrical device?

A radio transmitter does that. Just put your magnet next to a cell phone while talking.

What effects would you see? Probably nothing.
 
  • #9
grahas said:
Is there any way to achieve an alternating current with a frequency in the range of light, via a mechanical or electrical device?

yes, the standard way is to apply the correct amount of voltage to an appropriate light globe or LED ( Light Emitting Diode)
 
  • #10
davenn said:
yes, the standard way is to apply the correct amount of voltage to an appropriate light globe or LED ( Light Emitting Diode)
Note that does not actually create a 400,000 GHz AC current (electron flow). It creates a stream of photons with a frequency of 400,000 GHz
 
  • #11
meBigGuy said:
Note that does not actually create a 400,000 GHz AC current (electron flow). It creates a stream of photons with a frequency of 400,000 GHz

yes, I realize that ... but it's about the closest he is going to get :wink::rolleyes:
 
  • #12
I got it, and was sure you knew. Just wanted him to be clear.
 
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  • #13
meBigGuy said:
I got it, and was sure you knew. Just wanted him to be clear.

:smile:

grahas said:
Is there any way to achieve an alternating current with a frequency in the range of light, via a mechanical or electrical device?

I'm not aware of any way to do what he is asking. Even in the GHz microwave bands above around 30 GHz and up to several 100 GHz,
any oscillation within a Gunn diode or similar device, doesn't as an oscillation of electrons at that freq occur outside the device ( to my knowledge)Dave
 

1. What is a photo-resistor?

A photo-resistor, also known as a light-dependent resistor, is an electronic component that changes its resistance based on the amount of light it receives. It is commonly used in light-sensitive circuits.

2. How does a photo-resistor create an AC current?

A photo-resistor does not create an AC current on its own. It is simply a variable resistor that changes its resistance in response to light. In order to create an AC current, a photo-resistor would need to be part of a larger circuit that utilizes other components, such as a power source and a load.

3. Can a photo-resistor be used to generate electricity?

Technically, a photo-resistor can be used to generate electricity in certain situations. For example, if it is part of a circuit that includes a power source and a load, the varying resistance of the photo-resistor can cause fluctuations in the current and voltage, which can then be used to generate electricity. However, this is not the primary purpose of a photo-resistor and there are more efficient methods for generating electricity.

4. Is a photo-resistor considered an AC or DC component?

A photo-resistor is neither an AC or DC component on its own. Its resistance changes in response to light, regardless of whether the current in the circuit is AC or DC. However, when used in a circuit, the type of current will depend on the other components in the circuit.

5. What are some common uses for photo-resistors?

Photo-resistors are commonly used in light-sensitive applications, such as automatic light switches, streetlights, and camera light meters. They can also be used in burglar alarm systems and as part of solar cells. In general, they are used in any circuit where the amount of light needs to be measured or controlled.

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