LED lights use very little power and emit a bright light. They're ideal for many hobbyist applications, where you want to have a steady light source that can be run easily, and for a long time, with a battery. The standard rectangular 9-volt battery is an ideal power source for single or multiple LED lights.
- Skill level:
- Moderately Easy
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Things you need
- 9V battery connector (jack)
- soldering iron
- rosin core solder
Calculate the size of the resistor you'll need in your circuit. If you don't have a resistor in the circuit the LED will burn out very quickly. To calculate the size of resistor you need, use this formula: (power source volts minus LED light volts)/amp rating of the LED. For example, if your LED light has a rating of 3.5 volts, .02 amps, and the battery is 9V, the equation will read: (9-3.5)/.02 = 325. The resistor should be a 325 ohm resistor. If the exact value isn't available, go to the next highest rating available.
Strip the wire on the end of the 9V connector wires so about 3/8 of an inch of bare wire is exposed.
Place the positive wire of the LED against the positive (red) wire of the 9V battery connector. Place the tip of the soldering iron against the wires and hold it there, after several seconds, place solder on the wires so that it flows over and connects the wires. Remove the soldering iron.
Solder the negative lead of the LED to one end of the resistor, then solder the other end of the resistor to the negative (black) wire of the 9V battery connector. When the wires are cool, snap a 9V battery into the connector and the LED will light up.