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What is a typical response time for an LDR?
LDRs are light dependent resistors. Resistance decreases with increasing light levels. Typically > 1 MΩ when dark and < 1 kΩ in high light levels. Response time of 2 – 50 ms.
What is the wavelength bandwidth of typical LDR?
The use of the glass window on the microphone limits the spectral range used to wavelengths higher than 350 nm. LDR has not limitation and its spectrum beginning at 300 nm. Both spectra present absorption peaks at same positions: 420 nm and 490 nm.
Is LDR linear?
In general, the brighter the light, the lower the resistance, but unfortunately, the relationship between resistance and lux for an LDR is not a nice linear relationship. It is instead an exponential relationship which is a little trickier to deal with.
Which is the application of LDR?
Applications of LDR These devices are used where there is a need to sense the presence and absence of light is necessary. These resistors are used as light sensors and the applications of LDR mainly include alarm clocks, street lights, light intensity meters, burglar alarm circuits.
The LDR is a semiconductor component, hence it can translate light into a variation of resistance. Most LDR’s follow a curve (seen below) relating its resistance in respect of the light levels (in LUX) it is exposed to. Being a semiconductor makes its characteristic curve not be linear, instead an exponencial.
What is the resistance of a LDR resistor?
LDRs are light dependent resistors. Resistance decreases with increasing light levels. Typically > 1 MΩ when dark and < 1 kΩ in high light levels. Response time of 2 – 50 ms. (Much slower than photo-transistors.)
How does LDR affect the sensitivity of a photoresistor?
LDR frequency dependence. The sensitivity of photoresists is shown to vary with the wavelength of the light that is impacting the sensitive area of the device. The effect is very marked and it is found that if the wavelength is outside a given range then there is no noticeable effect.
What is the power dissipation capacity of a LDR?
The power dissipation capacity for a standard LDR could be around 50 and 500 milliwatts, which may depend on the quality of the material used for the detector. Perhaps the only thing not so good about LDRs or photoresistors is their slow response specification to light changes.