LDR (light dependend resistor)

Light dependend resistor is an electronic component capable of detecting lighimagen ldr

ldr-characteristic-curve

What is resistance?

The resistance measures the oposition of an electric current throught a conductor. The units are Ohms (Ω)

Electrical resistance, the measure of the degree to which a conductor opposes an electric current through that conductor (WIKIPEDIA DEFINITION).

What is ilumination?

Ilumination is the degree or intensity of light. The units to measure light are lux.

Examples:

Illuminance Surfaces illuminated by:
0.0001 lux Moonless, overcast night sky (starlight)
0.002 lux Moonless clear night sky with airglow
0.27–1.0 lux Full moon on a clear night
50 lux Family living room lights(Australia 1998)
100 lux Very dark overcast day
320–500 lux Office lighting
400 lux Sunrise or sunset on a clear day.
1000 lux Overcast day; typical TV studio lighting
1000025000 lux Full daylight (not direct sun)
32000100000 lux Direct sunlight

The numbers are not distributed linearly. It means that a number 0.0001 lux compared to 100000 lux are difficult to represent.

We need to represent using scientific numbers:

10^-4 = 0,0001

10^2 = 100

10^5 = 100000