DIY 12 Volt LED Light
By David Sandoval
Light emitting diodes (or LEDs) are electronic devices that emit light when a voltage differential is applied across the leads. Because LEDs emit very little heat when illuminated, LEDs use less energy than an incandescent light bulb of similar luminosity. LEDs last longer than incandescent bulbs and are used in applications where incandescent bulbs were the norm, such as flashlights and household lamps.
Materials and Tools Needed
To create an LED light (such as a flashlight or indicator light), at least four items are needed: an electrical switch, an LED, a DC power source, and a power conductor bus. The electrical switch is needed to close the circuit to turn the LED light on, and to open the circuit to turn the light off. A simple but reliable switching mechanism is the single-pole, single-throw (SPST) switch. Such a switch has two positions: on and off. Since the switch only has two terminals, one input terminal and one output terminal, wiring the switch as a circuit interrupter is easy to do.
When searching for an LED, choose one that is capable of handling the voltage output from the power supply. If too much voltage is applied, the LED will glow brightly for a few seconds and will fail quickly. If a 12V power supply is chosen to power the LED, choose an LED that is rated for at least 12V, such as the Sunbrite model SSP-4SE103S12G LED.
The power source should be either a battery or a regulated direct current (DC) power source. If the voltage and current coming from the power supply are not consistent, the LED may not receive enough power and will fail to illuminate. If the power supply is prone to power surges, the LED could be damaged by an over-voltage condition.
Electrical wiring is a common means for establishing a power bus between a power supply and electrical components. Choose electrical wiring that is capable of handling the voltage and current needs of the electrical circuit. A wire that is too thin will not be able to carry enough electrical current through the circuit.
Constructing the Electrical Circuit
To simplify circuit fabrication, the following tools and connectors are needed: electrical pliers, soldering iron, solder, and vinyl electrical tape. Cut a piece of wire, and strip each end of 1/2 inch of insulation. Since Light emitting diodes are polarized devices, the LED anode connection must always be connected to the positive (or higher voltage) connection, and the LED cathode lead must always be connected to the negative (or lower voltage) connection. Connect the wire from the positive power supply terminal to the anode, and solder the wire to the anode. For the Sunbrite model SSP-4SE103S12G LED, this connection is the bottom metal bump.
Cut a second length of wire, and strip each end of 1 inch of insulation. Connect the wire to the LED cathode (which is the screw connection on the Sunbrite model SSP-4SE103S12G LED), and solder the connection. Connect the other end of the wire to the input terminal on the switch, and solder the connection. Cut a third length of wire, and strip it of 1/2 inch of insulation at each end. Connect one end of this wire to the output terminal on the switch, and solder the connection. Connect the other end to the negative power supply terminal.
David Sandoval has served as a trainer and technical writer since 2000. He has written several articles online in the fields of home improvement, finance, electronics and science. Sandoval has an Associate of Applied Science in microelectronics from Northern New Mexico College.