Lets get started!
Step 1: What You Will Need
- x2 Ultra-Violet LED's. (I purchased mine from Radio Shack for under 2 bucks.)
- x1 100-Ohm Resistor (Again, from Radio Shack. 99cents for a pack of 5.)
- x1 DEAD 9v Battery (or purchased 9v battery clip)
- x1 WORKING 9v Battery
- Basic Soldering Equipment.
Step 2: Extracting the 9v Terminal Clip
Step 3: Warm Up the Soldering Iron- Construction Begins
-Note: Be generous with the amount of solder to get the resistors lead firmly connected. I had a hard time getting it to stick well with minimal solder. Adding more will do the trick.
Once the Resistor is secured, bend it downward also bending the un-soldered lead parallel to the resistor. This keeps the circuit organized and compact.
Step 4: Soldering the LED's
First, with one LED, trim the POSITIVE (+) lead to about 1/4"
Next, with the other LED, trim the NEGATIVE (-) lead to 1/4" as well.
Once you have done this, you'll want to bend the shortened contacts both outwards at a 90� angle.
Last, solder the two shortened contacts together.
Refer to Picture
Step 5: Putting It All Together
-Note: If you look carefully into an LED, connected to the leads are two pieces of metal. One piece is significantly bigger than the other, that lead would be NEGATIVE (-). Leaving the smaller piece POSITIVE (+).
Step 6: Let There Be Light!
If UV isnt your taste, you can duplicate this same project using different colored LED's, but that would require a different resistor suitable for your LED.
How do you find out which resistor is right for the LED you want to use?
When buying LED's, specifications are usually given for the average operating voltage, and mA to illuminate the LED. With those values, you can plug them into a simple online calculator that will give you the best resistor for your needs. This calculator can be found here: http://led.linear1.org/led.wiz
Question: "I have 2 LED's, but they are salvaged, therefor I don't know their operating values to plug into the online calculator."
Answer: A good rule of thumb is not to run a LED on any more than 3v WITHOUT A RESISTOR unless specified to have a higher operating range. For LED's with unknown voltage and mA values, "diode forward" or operation voltage should be 3, and 20mA should work just fine.