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Suppliers' catalogues usually include tables of technical data for components such as LEDs. These tables contain a good deal of useful information in a compact form but they can be difficult to understand if you are not familiar with the abbreviations used.

The table below shows typical technical data for some 5mm diameter round LEDs with diffused packages (plastic bodies). Only three columns are important and these are shown in bold. Please see below for explanations of the quantities.

Type	Colour	IF max	VF typ.	VF max	VR max	Luminous intensity	View angle	Wavelength
Standard	Red	30mA	1.7V	2.1V	5V	5mcd @ 10mA	60°	660nm
Standard	Bright red	30mA	2.0V	2.5V	5V	80mcd @ 10mA	60°	625nm
Standard	Yellow	30mA	2.1V	2.5V	5V	32mcd @ 10mA	60°	590nm
Standard	Green	25mA	2.2V	2.5V	5V	32mcd @ 10mA	60°	565nm
High intensity	Blue	30mA	4.5V	5.5V	5V	60mcd @ 20mA	50°	430nm
Super bright	Red	30mA	1.85V	2.5V	5V	500mcd @ 20mA	60°	660nm
Low current	Red	30mA	1.7V	2.0V	5V	5mcd @ 2mA	60°	625nm

I_F max: Maximum forward current, forward just means with the LED connected correctly.

V_F typ.: Typical forward voltage, VL in the LED resistor calculation. This is about 2V, except for blue and white LEDs for which it is about 4V.

V_F max: Maximum forward voltage.

V_R max: Maximum reverse voltage. You can ignore this for LEDs connected the correct way round.

Luminous intensity: Brightness of the LED at the given current, mcd = millicandela.

Viewing angle: Standard LEDs have a viewing angle of 60°, others emit a narrower beam of about 30°.

Wavelength: The peak wavelength of the light emitted, this determines the colour of the LED. nm = nanometre.

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