LED light bulbs are currently more expensive than traditional light bulbs, but the cost has been reduced by 90 percent over the last several years.Light bulb makers have developed a way to make a standard light bulb that uses LEDs for its light source.An LED is no longer considered useful when it has lost 30 percent of its brightness. Last much longer than traditional light bulbs, but they will fade over time.Voltages higher than labeled on the LED packaging will result in a LED that is destroyed. This voltage is typically between 1.5 volts and 3.6 volts. All LEDs are made with a maximum voltage they can connect to without being destroyed.If the LED is connected backwards it will not light up. The anode leg is connected in a circuit towards the positive terminal of the battery. The anode leg helps direct current from the p-type material to the cathode.The shorter LED leg is known as the cathode. The longer LED leg is known as the anode. The legs, called leads, also help pull heat away from the LED circuit. A LED has two legs that are used to connect it into a circuit.An epoxy case surrounds the LED circuit, providing a defined color and protection of the circuit.A small reflector (like the reflector surrounding a car headlight lamp) surrounds the semiconductor crystal, making the LED brighter.When current is allowed to flow from the p-type material to the n-type material, the LED emits light. These two materials give the LED the ability to light up. The LED semiconductor has n-type (negative) and p-type (positive) material.When the crystal is energized with electrical current, the semiconductor emits light. A LED lights up by using a small semiconductor crystal.

How the led works