A quick look at photoresistors

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A quick look at photoresistors in this video. Photoresistors or LDR's are a semiconductor electronic component that increases or decreases in resistance depending on the light that falls on it.

[@zenzen9131]

Good tutorial. Another common way of detecting light is to use an LED as a sensor ! Not a lot of people are aware that they can also act as simple photo diodes. Lots of examples on TH-cam of their application in this way :)

[@Dr_Mario2007]

Another thing about the photoresistors, is that majority of them, being of usual Cadmium Sulfide, are actually slow at reacting to anything compared to photodiode and phototransistor which is easily discoverable with LED flashlight that you know has higher frequency PWM (beyond 10kHz) and an oscilloscope.

[@UndernetSystems]

Thank you for this great video my friend.

[@learnelectronics]

+The Tinkering Corner You are welcome. New videos every day!! If there is anything you'd like me to cover, feel free to ask.

[@Venomator.]

Awesomesauce Paul, two videos on the trot with a new gadge, a project and little or no cost, thank you kindly - my marriage is saved, again... 👍🏻💡🐍

[@learnelectronics]

Always glad to help

[@CHANDSOME]

How could I build this circuit myself??

[@michaelpadovani9566]

Simplest method to implememt this application. Also, and correct me if I'm wrong, but the slight increase in LED brightness when u first move your hand over is due to the *proportional* voltage increase in the trans base? Nice effect compared to strictly on/off from a non-pwm pin.

[@learnelectronics]

+Michael Padovani You are correct

[@samehwaheed3882]

you are exlant man thank you

[@Red-Feather]

Hi. I did it without the transistor. What’s the use of the transistor in this setup?

[@mrgreenswelding2853]

Do you need to use a transistor?

[@jameselliott9397]

I am trying to figure out what is the best resistance values and size for a sun tracker.. using Arduino.

[@markdavis4754]

If you have enough of these connected together in parallel would it work as a solar panel?

[@learnelectronics]

You would get voltage, but I doubt any current

[@georgechambers3197]

Thanks for another fun circuit. I seem to remember something like this in one of Forest Mimms books. Cool stuff.

[@learnelectronics]

+George Chambers Though it's not in the curriculum, I encourage my students to purchase The Engineer's Notebook.

[@georgechambers3197]

I have quite a few of bis books I've picked up over the years. Great stuff.

[@learnelectronics]

+George Chambers Should be required reading for everyone involved in electronics.