I want to connect 2 leds in parallel. Each of them have forward v. of 2V and current draw at 20mA. I want to use single resistor.
So the calculation is:
(3.3V - 2V)/0.04A = ~32ohms resistor i need to protect the LEDS?
But i also have to protect the Pi which should output max of 16mA per 3.3 GPIO pin. With ~32ohms resistor pin will be forced to give 40mA, which out of a question is bad.
So to protect the pin also i will need another calculation for the parallel circuit. I will have to give up of some mA (led brightness) and lets say i can live with 4mA per LED.
So the new calculation is: (3.3V - 2V)/0.008A = ~162ohms right?
And since i have few 330ohm resitors, then (3.3V - 2V)/330 = ~4mA , devided by two for each LED = ~2mA per LED under this configuration.
Is that right?
Please, look the attached image and tell me, am i on the right direction?
Thank you and sorry if i am too "can smell it from distance" type of NOOB