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An LDR is a light dependent resistor, which is usually used to detect light levels, either ambient or reflected. The LDR works because incoming light carries energy, which can elevate the energy levels of electrons in a suitable medium to join the 'conduction band' which means that there are more charge carriers in the LDR, and hence the cell has lower resistance.
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When an LDR detects light or dark how long does it take for its resistance to change?
20 seconds
Does electric current remain constant in a circuit?
No it depends on voltage and circuit resistance and other physical parameter which affect the properties of component used in circuitry like - temperature pressure humidity light(in light sensitive circuit- LDR photo diode,photo transistor,) and other.
What is the function of an LDR or a TDR in an circuit?
The function of an LDR or light dependent resistor is to change the brightness of the light based weather conditions or light hitting the object the LDR is on. When it is darker out, the light does not shine as brightly.
What does an LDR cost?
about 13 p each but would be cheaper if bought together
Construction and working of electronic eye as a alarm?
THEORY AND CIRCUIT DIAGRAMCircuit Diagram of Electronic Eye Electronic eye has much use in this electronic age. Also Known as magic eye. It can be used as an automatic guest indicator at the door, If fitted on the bottom of the door entrance. Once it is installed at the door there is no need to install a call bell. It can also be used at homes or in banks as a burglar alarm.Fix the LDR to the wooden door or a locker to be protected in such a manner that when anybody tries to open it, a shadow falls on the LDR and the circuit gets activated and produce a pleasant sound through the buzzer.This electronic eye circuit uses NOT gate from CMOS I.CCD 4049. CD 4049 contains 6 independent NOT gate in one package; we have used here (a) one only. NOT gate output goes high(1) when the input pin 3 is at lower then 1/3rd level of the supply voltage. Conversely the output goes low (0) when it is above 1/3rd level. So small change in the voltage of pin-2 is enough to change the level of output (pin-3) from 1 to 0 and 0 to 1. The output has only two states high and low and can not remain in any intermediate stage. It is powered by a 9V battery for portable use. The circuit is economic in power consumption. Pin 1 is connected to the positive supply and pin 8 is grounded.To detect the present of an object we have used LDR and a source of light. LDR is a special type of resistance whose value depends on the brightness of the light which is falling on it. It has resistance of about 1 mega ohm when in total darkness, but a resistance of only about 5k ohms when brightness illuminated. It responds to a large part of light spectrum.We have made a potential divider circuit with LDR and 220 KΩ resistance connected in series. We know that voltage is directly proportional to conductance so more voltage we will get from this divider when LDR is getting light and low voltage in darkness. This divided voltage is given to input of NOT gate.As soon as LDR gets dark the voltage of input not gate drops 1/3rd of the supply voltage and pin 2 gets high and LED or buzzer which is connected to the output gets activated.Advantage of using Logic gate is that data can be easily send to other digital interface device.one can easily fed data to computer using parallel port or for further processing .
What is an LDR symbol?
An LDR is a Light dependent resistor.
What is the meaning of LDR?
LDR refers to Light Dependent Resistor.
What does a LDR sense?
light
What does LDR stand for?
Light Dependent Resistor LDR also means long distance relationship.
What happens to an LDR when a bright light is shined upon it?
When LDR is exposed to light energy . Due to light energy incident on LDR surface, free electron movement of an atom is increased in LDR. This causes high conduction of curent flowing through LDR. beause of free electron movement in LDR, resitance get decreased.
How do you measure light intencity?
Measure Light Intensity using Light Dependent Resistor (LDR) The resistance of the Light Dependent Resistor (LDR) varies according to the amount of light that falls on it. The relationship between the resistance RL and light intensity Lux for a typical LDR is RL = 500 / Lux Kohm With the LDR connected to 5V through a 3.3K resistor, the output voltage of the LDR is Vo = 5*RL / (RL+3.3) Reworking the equation, we obtain the light intensity Lux = (2500/Vo - 500)/3.3 For a low cost LDR, at the same light intensity, the part to part variation in resistance can be as high as 50%. Therefore such a low cost LDR is seldom used for measuring light intensity but more for light presence/absence detection.
What is the difference between LDR and LED?
An LED is an electircal component which converts electrical energy into light energy whereas an LDR uses light to complete the circuit and maintain the flow of current.
What is a use of a ldr?
its a light dependant resistor xx
In technology what does LDR stand for?
Light dependent resistor.
What are the advantages and disadvantages of light dependent resistor?
itroduction on LDR
Explain the working of LDR and mention any five applications of LDR in detail?
A photoresistor, light dependent resistor (LDR) or cadmium sulfide (CdS) cell is a resistor whose resistancedecreases with increasing incident light intensity. It can also be referred to as a photoconductor.Applications:camera light meters, street lights, clock radios, alarms, and outdoor clocks
What is a LDR dependent AC dimmer?
The LDR dependent AC dimmer is a Light Dependent Resistor which works by chopping off the parts of the AC voltage.
