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Basic LED Attributes

written by: Terry Ligard • edited by: Lamar Stonecypher • updated: 1/16/2010

LEDs are used extensively in robots, or any electronic device for that matter. The main reason for this is that LEDs come in a large variety of shapes, sizes, and colors. This allows for many different functions, such as simple traffic lights, to more complicated devices, such as digital clocks.

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    Light Emitting Diodes (LEDs) are very common components in any electronic device. Their function is to transform electrical energy into visible light. Moreover, they are inexpensive, durable, and are available in a number of sizes and colors.

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    LED Sizes

    • Standard sized T1-3/4 infrared emitting LED:   One of the most common LED size is the T 1 ¾. The “T" indicates the bullet shape and the 1 ¾ indicates the diameter measured in 1/8ths of an inch. The T 1 ¾ is considered a standard, as it is the most inexpensive and comes in the largest range of colors. Indeed, the smaller T 1 LEDs are more modern, as they use up less space, and the surface mount LEDs are even smaller, but are not used often for experimentation.

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    LED Shapes

    LED shape varieties   Single LEDs exist in a considerable array of shapes and mounts. Although the bullet shape is the most common, the side view and square types are also available. The shape of the LED can behave as either a light straightening lens or a light distributing lens. Multiple LEDs exist in a package. These are very common in digital clocks. Specifically, the different packages receive electric current at specific times to display the numerals.

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    LED Lens Clarities

    Currently, there exists three common lens clarities: water-clear, white diffused, and color diffused.

    Water-clear LED lenses are composed of a transparent plastic. They are a little brighter because the transparency of the lens does not allow for absorption or dispersion of the light. This type of lens is a light straightening lens, and is used in devices such as flashlights or traffic lights.

    White diffused LED lenses are opaque, in that they are cloudy. These types of lenses act to disperse the light, thus making it possible to view from all sides. As opposed to the water-clear LED, the opaque lens absorbs the light and spreads it over a greater viewing angle. Common uses for white diffused lenses are for power and ready status.

    Color diffused LED lenses are essentially the same as white diffused lenses, except they are tinted in a specific color. Therefore, colored lenses also spread the light consistently on all sides, but in a colored light.

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    Water-clear LED lensWhite diffused LED lensColor diffused LED lens
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    LED Viewing Angles

    The viewing angle of a specific LED indicates the extent to which the light disperses out. However, viewing angles are only applicable with water-clear lenses, since they focus the light head on.

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    LED Colors

    LED color variety   LEDs are available in a variety of colors for commercial production. The colors red, orange, yellow, and yellow-green are the most readily available, whereas true green, blue, and white are not as much, due to their higher costs. Fortunately, cheaper means of production will allow for the latter LEDs to grow in use for experimenters in robotics.

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    Related Reading

    How to Test an LED Lamp - Anybody experimenting with robotics or building a custom circuit will need to know how to test an LED light. For this, one requires a multimeter and the particular LED to be tested. Obtaining the voltage consumption of the LED will aid one in assessing the required battery life needed to sustain the circuit.