Apr 1, 2018 · Without the fixed resistor, the 5V going into the photoresistor has nowhere to go other than the analog input pin, so you'd read 5V regardless of the light level. The variable resistance of the PR combined with the fixed resistor forms a voltage divider which puts a variable voltage on the input.

I mean, photoresistor is already a resistor, why do we have to decrease the voltage in the circuit with an additional resistor? Thanks in advance for your answers.

Oct 15, 2020 · A photoresistor's sensitivity is a byproduct of the chemical used to create it. This one, a CdS cell, peaks around 545 nm wavelength, which means it is much more sensitive with Green, Green-Yellow light than it is UV/Violet/Blue or Red/IR.

Jul 12, 2021 · Why do most of dark sensor circuits in the Internet look like this? It seems to me that in such circuit, photoresistor doesn't limit base current and it doesn't work. I think that photoresistor sh...

Sep 11, 2023 · Tuning photoresistor circuit with resistors Ask Question Asked 1 year, 10 months ago Modified 1 year, 10 months ago

May 10, 2019 · I built a working sensor using the arduino starter kit photoresistor (datasheet) using a 10kOhm resistor and a 5V source but want to understand it better. Edit: afer helpful comments, this question is basically: a) what is the difference between a photodiode and -resistor b) why does a voltage divider need 2 resistors

Oct 1, 2015 · I'm doing a school project in which I need to measure the amount of light emitted by a specific object. The first thing that came to my mind was to use a photo resistor hooked up to a voltage mete...

Jul 29, 2019 · Question Now I need to measure the real-time resistance change of the photoresistor over a larger resistance range (1k to 100M). Is there a way to improve this circuit, to be able to measure the dynamic resistance values of the photoresistor over at least five magnitudes (1k to 100M)?

Dec 14, 2010 · Tie your photoresistor from the positive side of the power supply to the wiper on the variable resistor. That way the variable resistor will change both the charge time and the sensitivity to light.

Nov 8, 2020 · 5 As an addition to the other answers, typical CdS photoresistors have their maximum sensitivy at green light and nearly none for red and infrared. Also, their sensitive area is very uneven because of the electrode meanders. That makes pairing a red, bundled light source as a typical laser diode and a typical photoresistor a very bad choice.