Why would you think there wouldn't be a voltage drop if they are in parallel?Thank you for being so helpful.
I am going to have the LED's in parallel so I don't think there will be a voltage drop.
As long as there is not a maximum voltage I think I am OK.
Is there a minimum Amps to start an LED?
This is probably not a workable. 5 LEDs at 2.5V apiece would be 12.5V meaning that you need to drop the other 2.5V across the current limiting resistor. But if the voltage of the LEDs is high or low by 10%, then you would have a change of about 50% in your LED current, which is probably not acceptable. The more voltage you drop across the current limiting resistor (as a fraction of the voltage dropped across the LEDs) the more accurate and stable your LED current will be. On the other hand, you will be dumping a higher fraction of your power in the current limiting resistor. That's the basic tradeoff -- stability for efficiency.Thank you for this. I am being saved from making a lot of mistakes.
So if I was having 50 LED's
the circuit was at 15 volts,
the LED's had a voltage drop of 2.5 v
this would be enough for 5 LED's in series.
and I would need 10 lines of 5 LED's each line with its own resistor.?
If the OP is willing to test select the resistor (tweak the value for the current required) it could work, but this is usually more trouble than people are willing to go to.
For the most part, LEDs of the same part number will put out very close to the same brightness for the same amount of current through them. By putting them in series, you force them to have the same current.brilliant thank you this is such a great way of learning so much good information I will spend time looking through this.
There is one thing I do not understand I put out 7 red LED's in series on 13 volts they all light ok. I was expecting them to be different brightness as they would be the same amps, but the 1st would have 12 volts second 10 volts the 3rd 8 volts ect. But they were all the same brightness so is it the volt drop x amps = watts ?
I did read it but I will give it another go as i see new things each time and there were many articlesHello,
Did you read this post of the thread made by Bill_marsden?
http://forum.allaboutcircuits.com/showpost.php?p=117637&postcount=2
I gave you a link to the thread yesterday.
This should make clear how to connect your leds.
Bertus