This is because the Arduino has analog pins making it super easy to read the value from something such as an analog sensor.
The resistance is very high in darkness, almost high as 1MΩ but when there is light that falls on the LDR, the resistance is falling down to a few KΩ (10-20kΩ @ 10 lux, 2-4kOmega; @ 100 lux) depending on the model. The LED lights up when the intensity of the light reaching the LDR resistor is sufficient. A 230v AC supply is provided to the load (in this case, the load is represented with a lamp). Een lichtgevoelige weerstand ook LDR (Light Dependent Resistor) is een component waarvan de weerstand hoger wordt bij minder licht.
LDR Light Dependent Resistor / Sensor (LDR) Rs 5/ Piece Get Latest Price Application : Light dependent resistors, LDRs or photoresistors are often used in circuits where it is necessary The most common light sensor type that’s used in a light sensor circuit are photoresistors, also known as a light-dependent resistor (LDR). LDR is Light-dependent Resistor. LDR is a photoresistor that is used for the detection of light. In addition to emitting light, an LED can be used as a photodiode light sensor / detector. Wanneer het licht is, dan is de weerstand ongeveer 20KΩ. Here automatic night lamp circuit using LDR is given. This capability may be used in a variety of applications including ambient light level sensor and bidirectional communications. In het donker is de weerstand erg groot. Dan kan het wel tot 10 000 000 ohm. Light dependent resistors come in … When Light intensity high on LDR, The Resistance through it Decrease and When Light intensity is Low on LDR, then the resistance through it will Increase and Go very High. Here advantages and disadvantages of LDR are given. If a basic light sensor is needed, an LDR circuit such as the one in the figure can be used. De afkorting LDR betekend lightdepent resistance.

It is a light sensor circuit with relay output light activated switch. A photoresistor or LDR (Light Dependent Resistor), as the name suggests will change it resistance based on the light around it. hi am still not clear on how LDR can be use as a switch in turning light on in the dark knowing full well that the resistace during dark period is high base on low light intensity but if is at the day time is very clear that as the light intensity increases the resistance drop and at a certain light intensity current flows and switching can now be archieved that is in the day time. This is very similar to the Raspberry Pi LDR sensor tutorial, but our circuit & code is a lot easier. So, I decided to alter the resistor value from M to K range to use a standard photodiode as the ambient light sensor. in darkness, the resistance of Light Dependent Resistor is in the order of mega Ohms. LDR (Light Dependent Resistor) Based Light Sensor using Arduino Pradeep Singh | 18th Nov 2017 In this article, you will find, how to create a light sensor that can act as the basis for some other automation, for example, a light bulb that turns on at the dusk and turns off at the dawn etc. De weerstand van de LDR is afhankelijk van de hoeveelheid licht.