LEDs (light emitting diodes) operate at voltages of between 1 and 4 volts and are used in most electrical appliances to indicate various functions. They are widely used in holiday and landscaping lights as they last a long time and their power consumption is low. Wiring LEDs in parallel maintains the same output voltage throughout the lighting system and ensures that if one LED fails the others remain on. Wiring in parallel protects other LEDs in the chain as the voltage supplied to each LED remains the same, however many fail.
Line your LEDs on a suitable work surface. Use as many as you need. Each LED has two wires protruding from it. The shorter wire is the negative terminal and the longer is the positive. It's important to identify the two terminals as wiring the wrong terminals means they won't work.
Cut a length of twin AWG 18 wire enough to allow you to wire as many LEDs in parallel as you need. Low-voltage speaker wire works fine as it has two wires moulded together and the wires are colour coded red and black. Ensure you cut enough to connect to your power source. Lay your wire on the work surface.
Mark your wires with a marker pen at equal distances along the wire to match the number of LEDs you're wiring. Ensure you leave a reasonable gap between the last LED and the power source.
Strip 1/4-inch of plastic from both ends of the twin wires using wire strippers or a small knife. Trim 1/8-inch of plastic at each place you made a mark with your marker pen. Don't cut through the wire. Use a small knife to remove a small piece of plastic coating to reveal the inner metal wire.
Attach one end of the red coloured wire to the positive (long) terminal on your first LED. Connect the end of the black wire to the negative (short) terminal of your first LED. Use a small strip of electrical insulating tape to attach each wire to the terminals ensuring the negative and positive wires cannot touch each other.
Insert the second LED into the next place on your wire. This is one of the places you removed the plastic coating. The long terminal from the LED is inserted in the red (positive) exposed wire: the short terminal goes into the black (negative) wire. Wrap a small strip of electrical insulating tape around each terminal ensuring the two terminals are separate.
Repeat the process for the remaining LEDs. Always ensure you connect negative to negative and positive to positive.
Check each LED to make certain the terminals are securely attached and the terminals are insulated from each other.
Place your power source on the work surface. Your power source needs to match the voltage of one LED. Usually a 1.5-volt battery is fine, but the more lights in the parallel chain, the more energy gets drawn from the battery so if you're using a regular AA size battery it may not last long. Depending on the number of LEDs you are wiring you may need to get a larger battery with the same output voltage.
Attach the opposite end of the red wire to the positive terminal of your battery and the black wire to the negative terminal of your battery. Use insulating tape. Your parallel wired LEDs are illuminated.