I don't know how to thank you. I was so confused that I was almost ready to give up. Your video really explained the concept very well that I wanted to know so badly. Thank you so much 🥰
I have looked everywhere to have this explained to me - absolutely brilliant. Thank you ! I just couldn't understand how a LDR could turn a nightlight on, since in low light the resistance is high. Only doing GCSE Physicis (trilology), but there was a 6 mark question at the end and I was really struggling with. Thank you so so much.
I was so confused how the ldr worked when the resistance is high if it’s dark. This video just made me understand it 100%. Best explanation on the internet. Thanks
Literally the best piece of work I encountered regarding the topic.......none of my text book or any other platform on internet served as I require......the only video I found to enlighten my concept and spark magnificent learning And understanding Fully contented
you helped me a million fold with this, thank you for explaining so easy to comprehend, and now my mother in law who.lives in the jungle of mexico will have a solar light and won't have to flick a switch, thank you may god bless you and keep blessing you
I have been watching 3 videos so far and yours is the best explained, very clear concept and a great understanding. This video answered most of the questions l am confused about- thank you❤
Thank you for the explanation. I had a power line crew running secondaries to streetlights. I asked them if they isolated the feed and they said it didn't matter because the photocell isolated the power from one streetlight to another. Your video explained to me how wrong they were and the potential for injury was real.
Read through Wikipedia, watched multiple RUclips videos, and it wasn't until I watched your video that I finally understood what photoresistors are and what they do. Either I'm really stupid or you are a good teacher. Thanks!
As you accept ,'its not very efficient', but the basic theory of LDR & how it works has very nicely been explained, just like a professor explains in the classroom on a black board. Keep it up, Mortimer123. Very useful for the students.
Perfectly explained, I was literally thinking about the logic of why is resistance increased at night when clearly current will be less, but now I understand so thanks for that. But just wondering is there an easier way than this to turn street lights on because this method is a sort of reverse psychology kind of method, isnt there a faster method where amount of amps is regulated to low/high staright away and doesn't need an ldr in a circuit?
Thanks a Lottt. I was getting so confused while writing the working, that if the resistance is high there is no current flow so that should have meant the streetlights would not turn on in the dark...
Mr Lall, A serial setup is not useless. If you connect a solar battery charger to a battery, you would want current to flow through the circuit when the solar panel is in the sun (or daylight). But you do not want current to flow when the voltage generated by the solar panel is too low (or zero) to charge the battery because the solar panel is not generating enough power in the shade or in the dark. I purchased a solar charger that has an LED that indicates when the panel is producing some voltage. The problem is that the LED is in a plug that is inserted into the cigarette lighter socket. At night, when the solar panel is not generating electricity, the LED remains lit and drains down the battery. I do not know what else in the solar charger circuit is draining the battery but the battery voltage when down when I forgot to unplug the charger at sunset. Do LDRs come in different sizes capable of conducting different amount of current or are they used in circuit that require a transistor to amplify the current flow?
Well there is the secret I have been missing, what every electrician needs, a big metal bracelet to dangle over your circuit board. Anyway great video I gave a thumbs up
i finally understand why a lamp at night turns on when the resistance of the LDR is high- essentially the flow prefers flowing through the lamp as there is less resistance. Likewise, during the daytime when the LDR's resistor is low, the current mostly flows through the main part of the circuit, not the parallel bit. The lamp could have a slightly higher resistance than LDR
How much I had to search to eventually understand how LDR is used to control lights. Such a simple explanation! Everywhere you look you find the same thing, resistance of LDR increases as the intensity of light decreases and vice versa but how does that explain the use of LDR in controlling lights? I just understood without even watching the whole video. Thanks
but this would mean that you'll always be drawing 120w (based on your numbers) regardless whether the light is on or off right? is it possible to use a mosfet here? would be jice if you can provide an example
to help control the current that is flowing to the bulb, the fixed resistor is for the bulb, not the LDR, u need it there otherwise the bulb will burn out as most battery will produce a lot more power than a bulb can handle.
when the dark the LDR resistance will be very high there for current flaws through the bulb ,when the light comes LDR resistance will be very law then current flaws through the LDR then what will happens to the battery its fully short cirkit
Hi there, I have been looking but not found a circuit / diagram /project to operate my house outside lights when we come home at night, not by vehicle movement but by using the car headlights which would be on a timer circuit for say 3 minutes maximum, all the projects seem to use ambient light to switch on exterior/street lighting, do you or can you give me any relevant information for such a project. Regards, Charlie.
The theory behind the potential divider is solid and well presented, but the circuit as a light sensor is compleatly useless and would not work at all unless you had a MASSIVE LDR capable ov dissipating as many watts as the bulb and would have to have a much lower on resistance than 1K to make sure the bulb was off. But indeed the potential divider is usually the first stage in a *real* nightfall sensor. ;)
Sir, if in your circuit during light(daytime) ldr has no resistance but the series resistance with ldr can consume power. And drastically there will be lot of loss of power (12^2/100)=1.44 watts/h
hello sir, i want to give the ldr output signal to my plc to operate the light in more fancy way. does it have the NO/NC contacts? if no, then how i use the logic
+Tamz basically, when the concept of electricity was first conceived they thought that it must flow from positive to negative despite any knowledge. But after the discovery of electrons when they realised it's negative to positive all the maths and equations had been done as positive to negative they have stuck with it and called it "conventional current" which is just how we use it even though it's wrong .
I still dont get it how that can possibly work when you just have slight changes on the current by changing the total resistance of the circuit. The equivalent resistance of that parallel resistors will always be smaller then the smallest resistor in parallel. I dont get it...If some one can explain what Im missing here I would be appreciated.
I think its because the photocell basically creates a short circuit. When light shines the resistance in the photocell becomes so low that most of the voltage bypasses the load (light bulb) and goes through the low resistance photocell ...when there is dark the resistance in the photocell becomes so high that the voltage take the lesser past of resistance and goes through the load. im not 100% sure but i think thats how it works...someone correct me if im wrong
Nice video however your circuit will be drawing 10amps whether or not the light is on. It would be better to use a mosfet to drive the light bulb so the resister/LDR network can operate at lower current then the bulb.
![I.N "HALLUCINATION" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/n5B5q1Hwt_U/mqdefault.jpg)
This is the best explanation I've search about ldr for whole 2 days. very easy to understand for normal people like me
I don't know how to thank you. I was so confused that I was almost ready to give up. Your video really explained the concept very well that I wanted to know so badly. Thank you so much 🥰
I have looked everywhere to have this explained to me - absolutely brilliant. Thank you ! I just couldn't understand how a LDR could turn a nightlight on, since in low light the resistance is high. Only doing GCSE Physicis (trilology), but there was a 6 mark question at the end and I was really struggling with. Thank you so so much.
I extremely concur with you dear
Bulb resistance is very low only in ohms and LDR still high in Kilo ohms how 1 amps current will go through LDR circuit during day in light.
I was so confused how the ldr worked when the resistance is high if it’s dark. This video just made me understand it 100%. Best explanation on the internet. Thanks
Literally the best piece of work I encountered regarding the topic.......none of my text book or any other platform on internet served as I require......the only video I found to enlighten my concept and spark magnificent learning And understanding
Fully contented
you helped me a million fold with this, thank you for explaining so easy to comprehend, and now my mother in law who.lives in the jungle of mexico will have a solar light and won't have to flick a switch, thank you may god bless you and keep blessing you
Watched in HD, gained maximum educational benefit. Great video, really easy to understand.
I have been watching 3 videos so far and yours is the best explained, very clear concept and a great understanding.
This video answered most of the questions l am confused about- thank you❤
THANKYOU SO MUCH! I could not understand this, despite 3 different revision guides and many other videos but now finally I get it!!!! THANKYOU!
Thankyou so much! This helped me loads! You explained it in the best way possible and I am really grateful that you uploaded this.
Thank you for the explanation. I had a power line crew running secondaries to streetlights. I asked them if they isolated the feed and they said it didn't matter because the photocell isolated the power from one streetlight to another. Your video explained to me how wrong they were and the potential for injury was real.
Read through Wikipedia, watched multiple RUclips videos, and it wasn't until I watched your video that I finally understood what photoresistors are and what they do. Either I'm really stupid or you are a good teacher. Thanks!
This is explained so badly in text books...thankyou so much for making it clear and easy to understand!
Best explained ldr video on RUclips so far Thanks a lot .
I've always wanted to understand this, thanks for explaining it very clear and simple!
Hi.
Just started Learning Basic Electronics from a Book.
Your Tutorial on the LDR, was first-class.
I am in the U.K.
i looked everywhere to understand and i finally came across this and thank you i finally understand!
Thank u sir I’ve been struggling with this concept for a couple weeks now! Great video!
Absolutely fantastic, beautiful, life changing some would say
A great educational video clip... We need loads more on tricky topics such as this please
You are soo practical .this small video clip meant a lot to me. I know about them but when we apply them we get stuck .thanks alot
As you accept ,'its not very efficient', but the basic theory of LDR & how it works has very nicely been explained, just like a professor explains in the classroom on a black board. Keep it up, Mortimer123. Very useful for the students.
So many people state you can use an LDR for e.g street lighting, but DO NOT EXPLAIN HOW, thank you sir!
Perfectly explained, I was literally thinking about the logic of why is resistance increased at night when clearly current will be less, but now I understand so thanks for that. But just wondering is there an easier way than this to turn street lights on because this method is a sort of reverse psychology kind of method, isnt there a faster method where amount of amps is regulated to low/high staright away and doesn't need an ldr in a circuit?
Thanks a Lottt.
I was getting so confused while writing the working, that if the resistance is high there is no current flow so that should have meant the streetlights would not turn on in the dark...
Brilliant explanation, very easy to understand- thank you!
Thanks a lot for this video. Helped me understand the context for my ISA in physics. Really well explained.
Thank you so much! This was such a quick and perfect explanation.
Great video - Very helpful. Thanks!
That was a fantastic explanation! Thank-you so much
Thank you so much for this clear explanation, I was really confused before but this has helped me so again thank you!! Really appreciated 🍃
Great explanation, easy to understand
Finally today i learn this thank you sirmay ALLAH bless you😉🤘
just subscribed.... Coz only you have explained the circuit and nobody else did....
Great video sir!
You my friend are an absolute legend
Mr Lall, A serial setup is not useless. If you connect a solar battery charger to a battery, you would want current to flow through the circuit when the solar panel is in the sun (or daylight). But you do not want current to flow when the voltage generated by the solar panel is too low (or zero) to charge the battery because the solar panel is not generating enough power in the shade or in the dark. I purchased a solar charger that has an LED that indicates when the panel is producing some voltage. The problem is that the LED is in a plug that is inserted into the cigarette lighter socket. At night, when the solar panel is not generating electricity, the LED remains lit and drains down the battery. I do not know what else in the solar charger circuit is draining the battery but the battery voltage when down when I forgot to unplug the charger at sunset. Do LDRs come in different sizes capable of conducting different amount of current or are they used in circuit that require a transistor to amplify the current flow?
Clear, straight forward explanation. Thank you
youre just brilliance at its peak!!!
Well there is the secret I have been missing, what every electrician needs, a big metal bracelet to dangle over your circuit board. Anyway great video I gave a thumbs up
Thanks :) Got my exam tomorrow helped me how to think of potential dividers, so yeah thanks ^^
Thanks, perfectly answered the question in the forefront of my mind!
that was amazing.I never thought it was this simple. realy thanks a lot
Thats wonderful, you're good at explaining!
i finally understand why a lamp at night turns on when the resistance of the LDR is high- essentially the flow prefers flowing through the lamp as there is less resistance. Likewise, during the daytime when the LDR's resistor is low, the current mostly flows through the main part of the circuit, not the parallel bit. The lamp could have a slightly higher resistance than LDR
actually, more like less current will flow through the LDR at night when it has a high resistance, leaving more for the filament bulb.
Really good. does this apply to 230v power supply?
very helpful video and it is so easy to understand
Thank you so much, this exactly answered my question!
It was very useful.
How can i use both IR sensor and LDR together to detect any object and to light get on automatically
How much I had to search to eventually understand how LDR is used to control lights. Such a simple explanation! Everywhere you look you find the same thing, resistance of LDR increases as the intensity of light decreases and vice versa but how does that explain the use of LDR in controlling lights? I just understood without even watching the whole video. Thanks
This is what i needed to finally make sense of electricity, thanks
but this would mean that you'll always be drawing 120w (based on your numbers) regardless whether the light is on or off right?
is it possible to use a mosfet here?
would be jice if you can provide an example
I saw a circuit diagram in the net where in addition of this circuit,2 BC547 transistors were added.What is their use...?
wonderful but will it work without transistor
to help control the current that is flowing to the bulb, the fixed resistor is for the bulb, not the LDR, u need it there otherwise the bulb will burn out as most battery will produce a lot more power than a bulb can handle.
I understand...have been wondering how street lights worked for yonks. Thanks!
Thank you so much...This was so clear, and simple..It helped a lot❤
Thanks for sharing. Dear can you please share the LDR circuit with 12 v relay for day/night bulb control.
Hello sir! Gr8 video! Just a qn… how abt when the light bulb is parallel to LDR? That set up will only be useful at night rite?
when the dark the LDR resistance will be very high there for current flaws through the bulb ,when the light comes LDR resistance will be very law then current flaws through the LDR then what will happens to the battery its fully short cirkit
very helpful, a great explanation!
thank you sooooooo much, i never understood until now
AMAZING EXPLANATION
THANK YOU SO MUCH SIR👍🏼❤️
Thanks for this video, it was very informative and helpful.
:D
Thank you so much wasn't getting the logic behind it but now I get it 😁
Why is there a fixed resistor
so you dont blow the led with the 12 volts
Nude Jawn thank you
thank you sooo much!!! you made it sound really easy!!! :D
Hi there,
I have been looking but not found a circuit / diagram /project to operate my house outside lights when we come home at night, not by vehicle movement but by using the car headlights which would be on a timer circuit for say 3 minutes maximum, all the projects seem to use ambient light to switch on exterior/street lighting, do you or can you give me any relevant information for such a project.
Regards, Charlie.
The theory behind the potential divider is solid and well presented, but the circuit as a light sensor is compleatly useless and would not work at all unless you had a MASSIVE LDR capable ov dissipating as many watts as the bulb and would have to have a much lower on resistance than 1K to make sure the bulb was off. But indeed the potential divider is usually the first stage in a *real* nightfall sensor. ;)
awesome explanation . . .thank you very much.
Thanks you so much, can you please do the same circuit, but with a transistor and explain the operation of it. That would be awesome if you could.
Sir, if in your circuit during light(daytime) ldr has no resistance but the series resistance with ldr can consume power.
And drastically there will be lot of loss of power (12^2/100)=1.44 watts/h
wow thank you so much, that makes so much more sense, that's so so helpful!
You're a legend mate. Really clear and helpful
Thanks man for the great explanation!!!
thanks sir . it's very nice circuit 🙏🏻
hello sir,
i want to give the ldr output signal to my plc to operate the light in more fancy way. does it have the NO/NC contacts? if no, then how i use the logic
Dude u r simply awesome
Thanks a lot for this video!👍
Thanks but why doesnt the current split evenly when light eg 5A through the ldr and 5A through the lamp
Really should do more videos. This is a better explanation than the previous ones i watched
thank you very much ,,, i want to add relay to this circuit how can i ,,, thanx
Can you explain this circuit again but with a npn transistor?
Thankyou so much! understand my ISA context now :)
So why they use transistor in this circuit ?
awesome...
it cleared my basics
could u give explanation on ic555
also
plZz ...
Great Explanation thanks!
awesome....
cleared my basics
I understand it now but doesn't electricity flow from negative to positive. so in this case what will happen. will it be the same.
+Tamz basically, when the concept of electricity was first conceived they thought that it must flow from positive to negative despite any knowledge. But after the discovery of electrons when they realised it's negative to positive all the maths and equations had been done as positive to negative they have stuck with it and called it "conventional current" which is just how we use it even though it's wrong .
omg im so happy i found this thanks a bunchh
Thank you so much
This was so clear
I still dont get it how that can possibly work when you just have slight changes on the current by changing the total resistance of the circuit. The equivalent resistance of that parallel resistors will always be smaller then the smallest resistor in parallel. I dont get it...If some one can explain what Im missing here I would be appreciated.
I think its because the photocell basically creates a short circuit. When light shines the resistance in the photocell becomes so low that most of the voltage bypasses the load (light bulb) and goes through the low resistance photocell ...when there is dark the resistance in the photocell becomes so high that the voltage take the lesser past of resistance and goes through the load. im not 100% sure but i think thats how it works...someone correct me if im wrong
Here transistor required or not ?
i want to make it using 240v and using cfl bulb what should i do
Nice video however your circuit will be drawing 10amps whether or not the light is on. It would be better to use a mosfet to drive the light bulb so the resister/LDR network can operate at lower current then the bulb.
lucid explanation..thnx alot
Inefficient circuit... isn't?
So it takes a shit pot if power to keep the light off???
But between 10k resistor and the small resitance of the bulb much of the current will flow through the bulb !!??
Why is the other resistor added?
To decrease the amount of current, to a safe value,that flows from the bulb..
Vishal Jangid Ahh okay, thank you
I want to make it..can u plz tell me wt shud i do.