Hand Lights

Step 3 Wire up your LEDS.

Solder the resistors to your LEDs.

Since 4.5 volts is too much for most LEDs you need to put a resistor in there to keep them from burning out.

In most cases a 47 ohm resister on each will work. Use the LED resistor calculator here to be sure. (The values for my LEDS: 4.5 volts, 3.5 forward volts, 25mA forward current, and 3 LEDs.)

It doesn't matter if you put them on the long or short end of the LED, just put them all on the same end so you don't get mixed up and have to spend 20 minutes desoldering them. (Like I did.)

Now would be a good time to check them with your battery pack to make sure you've got it right, The long end of the LED goes to the +, short to -.

If they all check out then solder the three LEDs together. (Or if you got one big, bight LED you skip this step.) Solder all the free ends of the LEDs together along with one side of your two conductor wire. Similarly connect the free ends of the resistors together with the other strand of your wire.

Apply some electrical tape or shrink tubing to prevent short circuits.

Now would be a good time to test it again and make sure they all light up and you don't have any short circuits.