I am working on building it right now. I plan to have it done in about 1 month. I will be posting a series of videos showing exactly how it is built once it is complete.
Good to note that the Vf is directly (about) related to the inverse of the LED emission wavelength...and to note that the "white" LED is a *blue* LED with phosphors costing it for wavelength conversion... Just a thought, or two...
BTW, you ought to note that Vf varies a lot with Vf; just measure the Vf across each LED with the different resistor values... I used to be responsible for 2x10 ^9 LEDs per year....
Yeah, that is a good point! I did mention the voltage and resistor value I was using (5V and 2K) but I did not clearly say the voltage drop will be different if you change the resistor value or voltage used.
If you mean a high power LED this would be a much larger LED than you would use in a breadboard. A high power LED would have a max current rating of 300 ma or greater. These typically use a constant current driver. The LED is typically surface mounted to a piece of aluminum to help dissipate heat. For breadboards the standard green LED actually has the highest light intensity value and the white LED has the second highest.
Interesting LED display. I just forego trying to figure out forward drop for any L:ED and simple install a resister to only allow around .020amps or less. And regardless what the LED forward voltage drop is, the LEDs of any type lights. And you will never ever blow any LED doing that...period!
Why does the 3V source + 3V Led Forward Voltage have a resistor of "Led Off"? I'm kinda confused what happens when the Source and Led Forward Voltage match and how to calculate limiting its brightness in this situation... as all calculations seem to try to devide a value of 0 (3V-3V=0V)/Amps. Lets say I would like to run my leds at 0,010A instead of 0,020A. I would then calculate 0/0,010 = 0 also... How is this done?
If the forward voltage drop of the LED is 3V and the power supply is 2.99V. The diode will not allow any current to pass so the LED is off. This would be like applying .5V to a diode that has a .6V voltage drop. No current passes. Even if it is slightly over there would be very little current. Say the power supply is 3.01 volts. Then the current is .01/100 Ohms which is .0001 amps. Current is flowing but not enough to visibly light the LED. In this case I am saying the LED is off. If you want to be a lower current value just use that as the max value and use the same equation.
@@GlobalScienceNetwork Thanks for you reply :). I actually needed to build a 12V cirquit of 6 leds that have a forward voltage of 2.0V. The catch is that the cirquit usage needed to stay below a certain amount of watt, so I could not shine at 100%, but was limited to, lets say 500ma. I put all Leds in series, but I could not calculate what resistance I would need to only let current flow of 500ma (about 40% of Led max power). I decided to try and measure the LED real forward voltage @ 2V with 500ma. I set current limiting to 500ma on my power supply, connected a single led to it, and slowly increased my voltage until I saw it reach the 500ma limit, what turned out to give me 1,53V. Going any higher would trigger the limiter. While increasing only the current (not voltage) I did not see the current growing, it stayed at 500ma, and only got higher if I increased the voltage by 0,05V. So.. assuming in my senario the Led Forward Voltage is not 2.0V, but 1,53V (at my current/power) I suddenly could do resistor calculations as I have volts over to do calculations with. I ended up making the cirquit with 6 leds in series + the current limiting resistor the calculation gave me, and this gave me a reasonable accurate result. When I removed the voltage drop of the resistor, and calculated the watts consumed by the Leds it actually was pretty close to what I needed. Thanks for this vid, and ya resonse, and I hope this post helps someone who is also getting confused by the Forward Voltage often displayed in documentation. The Forward Voltage does not seem to be the exact on/off point, but the point at witch the Led reaches a certain amount of output. In my case the led already started to turn on at 1,28V or so.
Why do you say that the brightness of the 5mm LED will be higher than the 3mm LED...if they have the same Vf at the same If, they are the same die size...the 5mm LED has more optical material, and can make a "tighter" beam, but the total light output is probably the same...
Interesting, that is a good point. I was going off the spec that a 3mm red LED light intensity was 1000-2000mcd and the 5mm was 2000-3000mcd. I think you are correct that it has to do with the beam width. So it lets off the same amount of light but the 5mm LED will be brighter at any given distance away if you are within the focused beam.
@@GlobalScienceNetwork yes, it's just that the MCD reading is a "point measurement", whereas the total output in Lumens is the power output...so, the LED die is the same 'brightness', but the 5 mm package allows for sharper focus and more of the radiation from the die to be captured...
@@GlobalScienceNetwork Sir, thank you for taking my comments in the way that they are intended...in truth, I would, in cases like this, prefer to use some kind of PM, instead of 'Comments'
@@lohikarhu734 It is nice that it is in the comments cause the video can not be edited. So comments are where people make additional points I did not think of when making the video.
Do you mean it broke or burned up? If that is the case there was not a resistor in to current path or the resistor was of two low of a value to limit the current.
The resistors don't limit the current. They set the current for a specified supply voltage. There is no current limiting effect whatsoever. Lets use the correct terminology please, terminology which accurately reflects what is going on.
A current limiting resistor is a common term used for LEDs. Without the resistor, the current will be very high and burn out the LED or reduce the LED life expectancy depending on the input voltage. With a properly sized resistor added, the current is reduced compared to not having a resistor, and the LED will be operating within the specification limits. I am pretty sure limit is meant to describe that the current is reduced, however, it could also mean that it sets the current not to exceed the max current rating or limit.
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The Vf's actually directly correspond to the wavelength.
Cool, I did not know that when making the video!
Have you ever made a breadboard computer with transistors? If you did, can you make a video?
I am working on building it right now. I plan to have it done in about 1 month. I will be posting a series of videos showing exactly how it is built once it is complete.
Good to note that the Vf is directly (about) related to the inverse of the LED emission wavelength...and to note that the "white" LED is a *blue* LED with phosphors costing it for wavelength conversion... Just a thought, or two...
Good points, thanks for sharing!
So good video 😊😊
Thank you very much for your efforts 🎉🎉❤❤
Sure thing! Thanks!
BTW, you ought to note that Vf varies a lot with Vf; just measure the Vf across each LED with the different resistor values... I used to be responsible for 2x10 ^9 LEDs per year....
Yeah, that is a good point! I did mention the voltage and resistor value I was using (5V and 2K) but I did not clearly say the voltage drop will be different if you change the resistor value or voltage used.
Can you recommend a power led?
If you mean a high power LED this would be a much larger LED than you would use in a breadboard. A high power LED would have a max current rating of 300 ma or greater. These typically use a constant current driver. The LED is typically surface mounted to a piece of aluminum to help dissipate heat. For breadboards the standard green LED actually has the highest light intensity value and the white LED has the second highest.
Interesting LED display. I just forego trying to figure out forward drop for any L:ED and simple install a resister to only allow around .020amps or less. And regardless what the LED forward voltage drop is, the LEDs of any type lights. And you will never ever blow any LED doing that...period!
Yeah, if you are not trying for max brightness you can just use 1K plus ohms resistor and you are good to go.
Why does the 3V source + 3V Led Forward Voltage have a resistor of "Led Off"? I'm kinda confused what happens when the Source and Led Forward Voltage match and how to calculate limiting its brightness in this situation... as all calculations seem to try to devide a value of 0 (3V-3V=0V)/Amps.
Lets say I would like to run my leds at 0,010A instead of 0,020A. I would then calculate 0/0,010 = 0 also... How is this done?
If the forward voltage drop of the LED is 3V and the power supply is 2.99V. The diode will not allow any current to pass so the LED is off. This would be like applying .5V to a diode that has a .6V voltage drop. No current passes. Even if it is slightly over there would be very little current. Say the power supply is 3.01 volts. Then the current is .01/100 Ohms which is .0001 amps. Current is flowing but not enough to visibly light the LED. In this case I am saying the LED is off. If you want to be a lower current value just use that as the max value and use the same equation.
@@GlobalScienceNetwork Thanks for you reply :). I actually needed to build a 12V cirquit of 6 leds that have a forward voltage of 2.0V. The catch is that the cirquit usage needed to stay below a certain amount of watt, so I could not shine at 100%, but was limited to, lets say 500ma. I put all Leds in series, but I could not calculate what resistance I would need to only let current flow of 500ma (about 40% of Led max power). I decided to try and measure the LED real forward voltage @ 2V with 500ma. I set current limiting to 500ma on my power supply, connected a single led to it, and slowly increased my voltage until I saw it reach the 500ma limit, what turned out to give me 1,53V. Going any higher would trigger the limiter. While increasing only the current (not voltage) I did not see the current growing, it stayed at 500ma, and only got higher if I increased the voltage by 0,05V. So.. assuming in my senario the Led Forward Voltage is not 2.0V, but 1,53V (at my current/power) I suddenly could do resistor calculations as I have volts over to do calculations with. I ended up making the cirquit with 6 leds in series + the current limiting resistor the calculation gave me, and this gave me a reasonable accurate result. When I removed the voltage drop of the resistor, and calculated the watts consumed by the Leds it actually was pretty close to what I needed. Thanks for this vid, and ya resonse, and I hope this post helps someone who is also getting confused by the Forward Voltage often displayed in documentation. The Forward Voltage does not seem to be the exact on/off point, but the point at witch the Led reaches a certain amount of output. In my case the led already started to turn on at 1,28V or so.
Why do you say that the brightness of the 5mm LED will be higher than the 3mm LED...if they have the same Vf at the same If, they are the same die size...the 5mm LED has more optical material, and can make a "tighter" beam, but the total light output is probably the same...
Interesting, that is a good point. I was going off the spec that a 3mm red LED light intensity was 1000-2000mcd and the 5mm was 2000-3000mcd. I think you are correct that it has to do with the beam width. So it lets off the same amount of light but the 5mm LED will be brighter at any given distance away if you are within the focused beam.
@@GlobalScienceNetwork yes, it's just that the MCD reading is a "point measurement", whereas the total output in Lumens is the power output...so, the LED die is the same 'brightness', but the 5 mm package allows for sharper focus and more of the radiation from the die to be captured...
@@lohikarhu734 Copy that, thanks for pointing this out!
@@GlobalScienceNetwork Sir, thank you for taking my comments in the way that they are intended...in truth, I would, in cases like this, prefer to use some kind of PM, instead of 'Comments'
@@lohikarhu734 It is nice that it is in the comments cause the video can not be edited. So comments are where people make additional points I did not think of when making the video.
My LED fused
Do you mean it broke or burned up? If that is the case there was not a resistor in to current path or the resistor was of two low of a value to limit the current.
The resistors don't limit the current. They set the current for a specified supply voltage. There is no current limiting effect whatsoever.
Lets use the correct terminology please, terminology which accurately reflects what is going on.
A current limiting resistor is a common term used for LEDs. Without the resistor, the current will be very high and burn out the LED or reduce the LED life expectancy depending on the input voltage. With a properly sized resistor added, the current is reduced compared to not having a resistor, and the LED will be operating within the specification limits. I am pretty sure limit is meant to describe that the current is reduced, however, it could also mean that it sets the current not to exceed the max current rating or limit.
Been using the term for 40 years, as does everyone else. That is the agreed upon term that we all use.