I believe your method is flawed. The precise value +/- should be calculated based on the applied voltage and the maximum current rating of the led. Too low of a resistance will shorten the life of the led and too high value will reduce the brightness.
The watts rating on a resistor is for power. The formula for power is:
P = I^2 R
where R is resistance and I is current. So a 1000 ohm resistor with a current of 1mA (10^-3 A) is dissipating 1000*( (10^-3)^2) W, or 10^-3 W. For most LEDs, 1/4 W resistors should be fine. (In my example, a 1/4W resistor would only be dissipating 1/250 of the power it can handle.) Normal LEDs only use a few mW.
Doing a precise calculation is certainly the best way when you have all of that information about the LED available. But if you don't, then picking the largest resistor that gives "reasonable" brightness should work. I assume people have little or no electronics background. For those who do, they shouldn't have any problem doing as you suggest.
A mistake people often make is to confuse resistance and current. A large resistor means a small current, and vice versa. So the 100 ohm resistor allows the most current (and so the brightest LED), while the 10kohm (or 10000 ohm) resistor allows the least current (and so the dimmest LED).
I use multi colour 10mm on my garden railway.
I use a resistor that gives a modeate light, and it never seems the right ohms .ccording to some internet experts.
I don't have a lot of experience with multi-colour LEDs, but it might be that the ideal resistance will be different for the different colours. In general, I'd say if the brightness is reasonable the resistance is probably OK.
Blue LEDs will light at a higher voltage than the other colours, so for the same supply voltage, the resistance will probably* be lower, but the process of choosing an appropriate resistor is the same.
*(I say "probably" because more efficient LEDs will require less current for the same brightness regardless of colour.)
question : ive read about making an aux input for my stereo, it says to put a 10 k ohm resistor between certian pins in order to trick the unit in to belivong that power is being drawn so that way the aux in mode can be activated. would i really need a resistor for this or could i just stick a paper clip in there like many do when testing mother boards
Using a paper clip would be a REALLY bad idea; that would short out the two pins. The 10k resistor will allow a small current to flow, to indicate something is connected. So definitely use the resistor.
well forget ohms law don't know what this video is trying to teach people its not using the correct resistor values for a led and Values not critical who Teach`ed you electronics anyone watching this go watch videos where a guy knows what he is on and know about disgusting video kids watch this if your gonna teach then get qualified
ok i want to replace the vu meters lamps in my power amp and the voltage at the lamps is 12 volts dc, i want blue leds, what resistor value i need for the blue led ?
Just what I needed to know, but couldn't you actually had left all the LEDs connected for us to see and compare at the same time? (They were connected in parallel, right?) Your hand kept getting in the way.
+Terry Sturtevant I think you forgot to mention the properties of power source i.e. Volts and Amps. Please explain their relation to your choice as well.
That's a great video! I have a question though… I do LED conversion on vehicle tail lights and I often use LED strips that have multiple LEDs connected together. In order for me to get a double function for running lights and brakes on the same LED strip, I use a resistor for two different brightness levels. I have successfully been using 220ohm 1/4watt 5% resistors for the past two years, but the last batch of LED strips I got do not work well with that resistor. What happens is that some of the strips would only light up partially and others won't even light up at all. I am assuming that this is due to the fact that the new LED strips have more LEDs built into them and that would require a resistor with a lower value of OHMs, in order to send enough power to all LEDs in the strip. Is that a correct conclusion or is there another problem that I am not seeing? Would it help to use 100ohm resistor, instead of the 220ohm or is there another solution? Or would I need a resistor with higher wattage, say 1/2watt instead of 1/4watt? Thank you very much!
what if you coming off 12 volt battery with high amperage from a car battery and you want to power color LED push plot switches for led interior lights I keep on blowing the plot switch diodes up and blowing the fuse
I have little LED lights in my car doors that activate mt "door ajar" warning light but very faintly, and when car is off the LEDs glow in the door dimly lit. the LED 5-SMD 12v my car is 12v what resistor would i need or would a resistor even work in this situation?. The bulbs are little 194 size bulbs. Thank you
Since several people have asked, I was using a 5V supply. Part of my point was that using any "common" sort of DC supply voltage, such as 5V, 9V, or 12V, the process I illustrated would work. As I mentioned below, if you know all of the electrical characteristics of the LEDs you're using, then you can do the calculations.
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so is that the gradiation scale of ohms from the brightest down to the weakest ohms? i thought that 510 ohms would provide a brighter effect.
how do you determin how many watts the resistor should be. i noticed they have ohms and watts option.
I believe your method is flawed. The precise value +/- should be calculated based on the applied voltage and the maximum current rating of the led. Too low of a resistance will shorten the life of the led and too high value will reduce the brightness.
The watts rating on a resistor is for power. The formula for power is:
P = I^2 R
where R is resistance and I is current. So a 1000 ohm resistor with a current of 1mA (10^-3 A) is dissipating 1000*( (10^-3)^2) W, or 10^-3 W. For most LEDs, 1/4 W resistors should be fine. (In my example, a 1/4W resistor would only be dissipating 1/250 of the power it can handle.) Normal LEDs only use a few mW.
Doing a precise calculation is certainly the best way when you have all of that information about the LED available. But if you don't, then picking the largest resistor that gives "reasonable" brightness should work. I assume people have little or no electronics background. For those who do, they shouldn't have any problem doing as you suggest.
A mistake people often make is to confuse resistance and current. A large resistor means a small current, and vice versa. So the 100 ohm resistor allows the most current (and so the brightest LED), while the 10kohm (or 10000 ohm) resistor allows the least current (and so the dimmest LED).
Your video was nice thanks man 🙂
I use multi colour 10mm on my garden railway.
I use a resistor that gives a modeate light, and it never seems the right ohms .ccording to some internet experts.
I don't have a lot of experience with multi-colour LEDs, but it might be that the ideal resistance will be different for the different colours. In general, I'd say if the brightness is reasonable the resistance is probably OK.
Blue LEDs will light at a higher voltage than the other colours, so for the same supply voltage, the resistance will probably* be lower, but the process of choosing an appropriate resistor is the same.
*(I say "probably" because more efficient LEDs will require less current for the same brightness regardless of colour.)
question : ive read about making an aux input for my stereo, it says to put a 10 k ohm resistor between certian pins in order to trick the unit in to belivong that power is being drawn so that way the aux in mode can be activated. would i really need a resistor for this or could i just stick a paper clip in there like many do when testing mother boards
Using a paper clip would be a REALLY bad idea; that would short out the two pins. The 10k resistor will allow a small current to flow, to indicate something is connected. So definitely use the resistor.
well forget ohms law don't know what this video is trying to teach people its not using the correct resistor values for a led and Values not critical who Teach`ed you electronics anyone watching this go watch videos where a guy knows what he is on and know about disgusting video kids watch this if your gonna teach then get qualified
brilliant tutorial and very informative
What is your voltage?
ok i want to replace the vu meters lamps in my power amp and the voltage at the lamps is 12 volts dc, i want blue leds, what resistor value i need for the blue led ?
thanks for the demo.
Just what I needed to know, but couldn't you actually had left all the LEDs connected for us to see and compare at the same time? (They were connected in parallel, right?) Your hand kept getting in the way.
+Terry Sturtevant I think you forgot to mention the properties of power source i.e. Volts and Amps. Please explain their relation to your choice as well.
That's a great video! I have a question though… I do LED conversion on vehicle tail lights and I often use LED strips that have multiple LEDs connected together. In order for me to get a double function for running lights and brakes on the same LED strip, I use a resistor for two different brightness levels. I have successfully been using 220ohm 1/4watt 5% resistors for the past two years, but the last batch of LED strips I got do not work well with that resistor. What happens is that some of the strips would only light up partially and others won't even light up at all. I am assuming that this is due to the fact that the new LED strips have more LEDs built into them and that would require a resistor with a lower value of OHMs, in order to send enough power to all LEDs in the strip. Is that a correct conclusion or is there another problem that I am not seeing? Would it help to use 100ohm resistor, instead of the 220ohm or is there another solution? Or would I need a resistor with higher wattage, say 1/2watt instead of 1/4watt? Thank you very much!
some advice. use a jumper wire so you not blocking the camera every 2 seconds.
Interesting but you didn't say what voltage your supply is
What was the source voltage?
If I connect 25 LED in series, what will be the battery voltage and resistance.
what if you coming off 12 volt battery with high amperage from a car battery and you want to power color LED push plot switches for led interior lights I keep on blowing the plot switch diodes up and blowing the fuse
what's the voltage?
what if i use a 220v what will happen with the LED
Hi.. What is the value of the led? ( I'm a beginner thanks!)
I have little LED lights in my car doors that activate mt "door ajar" warning light but very faintly, and when car is off the LEDs glow in the door dimly lit. the LED 5-SMD 12v my car is 12v what resistor would i need or would a resistor even work in this situation?. The bulbs are little 194 size bulbs. Thank you
Camera on the wrong side, not telling the voltage used, clumsy handling. Uploading DIY shit? Just find something else to do, you suck beyond believe!
Since several people have asked, I was using a 5V supply. Part of my point was that using any "common" sort of DC supply voltage, such as 5V, 9V, or 12V, the process I illustrated would work. As I mentioned below, if you know all of the electrical characteristics of the LEDs you're using, then you can do the calculations.
My science teacher required this, so thank you, so fricking much
I’ve noticed that anything under 330 ohms will result to over heating. Not recommended in modeling or closed enclosures.