liudr:
takao21106:
Grumpy_Mike:
What is worst are the morons that think resistors on LEDs are unnecessary.Resistors aren't really much used for power LEDs.
If a component is neccessary isn't defined by what someone thinks, but by the circuit, and the component specifications.If arduino has constant current supply it would not need a resistor either but it has a constant (to certain limit) voltage supply instead. You are totally mixing up these two situations. The arduino is the constant voltage situation and a resistor is always needed.
Good idea NI$HANT, the more specific hardware will depend on local suppliers too so I wish there were lists for parts suggestions say USA/UK/Australia/India/... where lots are playing with Arduino.
I did not write "resistors are not needed", or, "resistors are not needed for connecting LEDs to Arduino". I wrote it's defined by the component specification/circuit.
Actually, I will try now, connect one LED without resistor (to ATMega328), and measure the current. Of course using precaution, at first setting the port bit high, then carefully tapping the LED lead to the PCB.