I am sure this is a very basic question, but I just want to be sure to not make any mistakes. I am using a transistor S8050 D331 to switch leds. So the base is connected with 1K resistor to the Arduino Due (3,3V) outputs. The emitter is connected to ground. The collector is connected to 1 led and a series 220Ohm resistor. The collector voltage is a seperate 5V supply.
Now the leds are too bright. What base resistor do I need to use if I increase the led resistor value? How are those related?