I want to build a light for the top of my aquarium out of LED's. Can anyone show me how?

Question

I don't understand the resistors, and forward current and all that stuff. I want to be able to plug it in a wall outlet. Thanks.

Answer 1

First, how many leds do you have? What size stepdown transformer are you going to use?With 12 leds you will need a 9v xformer  (small plug in type)  the leds should be wired in series( ie +to - to +to - etc) with a small resistor in series as a current limitor(anywhere from 1k to 5k if to dim use lower resistance)