How to: drive common cathode led with Arduino?

Using Arduino General Electronics
14

Grumpy_Mike:
Dream on sunshine.

I think Mike may be trying to say you need to do a refresher on Ohm's Law.

P= I x E

I = P/E

I = 5/15

I = 1/3A

Quod erat demonstrandum, the current is greater than the 75mA you suggested by a factor of over 4.

Weedpharma