Effect of Light's intensity (distance of light source)on resistance of the LDR

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username2889812
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#1
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#1
Hi!
I'm trying to find secondary sources for this investigation....the effect of changing the distance of light source upon the resistance of the LDR
Couldn't find any (secondary evidence)graphs with log scales....
I took log Resistance in the y axis and log distance on the X axis...

Any links or sources of information (for secondary evidence) or the key words to be searched would be really (times infinity) helpful! :ta:
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uberteknik
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(Original post by Spannerin'moi)
Hi!
I'm trying to find secondary sources for this investigation....the effect of changing the distance of light source upon the resistance of the LDR
Couldn't find any (secondary evidence)graphs with log scales....
I took log Resistance in the y axis and log distance on the X axis...

Any links or sources of information (for secondary evidence) or the key words to be searched would be really (times infinity) helpful! :ta:
Luminous Intensity
Lux
Radiance
Irradiance
Inverse Square Law

Download LDR manufacturer's datasheet from RS components etc:

Here is the ORP12 device datasheet: https://docs-emea.rs-online.com/webd...6b8156674b.pdf
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username2889812
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(Original post by uberteknik)
Luminous Intensity
Lux
Radiance
Irradiance
Inverse Square Law

Download LDR manufacturer's datasheet from RS components etc:

Here is the ORP12 device datasheet: https://docs-emea.rs-online.com/webd...6b8156674b.pdf
Thanks a ton for the resource ...very credible and valid:yep:
but I was looking for X axis to be log (distance of the light source) instead of lux or intensity of light :hmmmm:
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uberteknik
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(Original post by Spannerin'moi)
Thanks a ton for the resource ...very credible and valid:yep:
but I was looking for X axis to be log (distance of the light source) instead of lux or intensity of light :hmmmm:
You will find the intensity of light falling on the LDR is a ratio of the surface area of the LDR and the total light output produced by the source.

As the distance from the source increases, the light received at the LDR falls away with the square of the distance because the light is received over the same surface area of the LDR, whilst the total light output from the source is spread over a larger surface area at that distance.

Lux is simply a reference light output. The ratio between irradiance and distance from the source is always a square law regardless of the units used.

Image
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username2889812
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(Original post by uberteknik)
You will find the intensity of light falling on the LDR is a ratio of the surface area of the LDR and the total light output produced by the source.

As the distance from the source increases, the light received at the LDR falls away with the square of the distance because the light is received over the same surface area of the LDR, whilst the total light output from the source is spread over a larger surface area at that distance.

Lux is simply a reference light output. The ratio between irradiance and distance from the source is always a square law regardless of the units used.

Image
PRSOM

I've been reigned over this line of thought ...that the primary and secondary evidence should have the same x and y types of values so that a good comparison could be made...I thought I'll need another secondary evidence graph to explain the relationship between intensity of light and distance....but if I could explain the relationship well, it should be good....
:ta: a bunch!
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username2889812
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#6
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(Original post by uberteknik)
You will find the intensity of light falling on the LDR is a ratio of the surface area of the LDR and the total light output produced by the source.

As the distance from the source increases, the light received at the LDR falls away with the square of the distance because the light is received over the same surface area of the LDR, whilst the total light output from the source is spread over a larger surface area at that distance.

Lux is simply a reference light output. The ratio between irradiance and distance from the source is always a square law regardless of the units used.

Image
I'm really sorry for the trouble but....wasn't the graph supposed to be non linear? The data sheet had it linear:hmmmm:
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