Hi
I wanted to ask a question on LEDs.
If i have a 3V3 supply and using a LED of 2.1V forward voltage and IF of 20mA.the mcd is 200. I tend not to run st full 20mA but give some head room so 15mA is what i normally use.
To calculate the required resistor is
R = 3V3-2.1V/15mA
How is this current related to luminous intensity i.e. mcd? Is it the more current the closer it gets to 200mcd?
Also if i have a pure green LED with VF of 3V, then i believe it is not worth trying to use with a 3V3 supply. Am i correct in this?
Thanks in advance.
I wanted to ask a question on LEDs.
If i have a 3V3 supply and using a LED of 2.1V forward voltage and IF of 20mA.the mcd is 200. I tend not to run st full 20mA but give some head room so 15mA is what i normally use.
To calculate the required resistor is
R = 3V3-2.1V/15mA
How is this current related to luminous intensity i.e. mcd? Is it the more current the closer it gets to 200mcd?
Also if i have a pure green LED with VF of 3V, then i believe it is not worth trying to use with a 3V3 supply. Am i correct in this?
Thanks in advance.