This is probably one of the easiest crcuits you'll ever deal with when building an electronic circuit. It consistes of three parts, a 9 volt battery, 1K ohm resistor, and a LED (Light Emitting Diode). All of these parts you can get from radio shack (what we call Rat Shack), ahem, or any other electronics place. Also, when getting the resistor, be sure to get a brown, blak, red coded resistor to ensure its a 1K, if it isnt, you may get the results below. If you dont want to mess with te color bands however, just ask for a 1K ohm resistor.. that'll be the right one. Its VERY important to the life of the led for you NOT to directly 'test' the led by connecting the led across the 9 volt battery. Doing so will result in what my teacher Mr. Krauss refers to as "MAGMA" :P It will get VeRy bright, then either smoke, get very hot and or pop, destroying the led. What do you think they teach us at college? Not much. Just Kidding!! They went in great detail to teach us about current and its powers: One of the things they emphasize is the current limiting properties of a resistor. Putting the 1K ohm resistor in series with the led limits the current throught the led and makes it light, but protects it from too much current. See the diagram below for circuit and parts list. Another thing you need to watch is the 2 legs of the led. One of these will b shorter than the other or have a flat spot above it on the epoxy part of the led. The one with this flat spot is the NEGATIVE side and will go towards the - side of the battery. Dont worry though, if you connect the led backwards, but be sure to use the 1K ohm resistor, you wont burn out the led, it just wont light. If this is the case, just reverse the leds legs and reconnect it. This is a simple circuit, and I have used it as a mini flashlight by adding a fer high-brightness leds in parallel with the one shown, but you neednt get into that now. all you need is the parts show, its pretty simple to do :) If you have any questions, you can email me at my address below, but depending on how full my mail is, and the bulk of activity during the week, I cant guarantee when I'll be able to get back to you, although I WILL send you a reply if at all possible :) Have fun building it and 'Let there be light!' --Josh Sawyer (KG4SPO)