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Light Emitting Diodes (LEDs)• LEDs are used as indicator lamps in may
devices and are becoming increasingly used for other lighting purposes, such as projectors, torches and TVs.
• LED colours are based on the wavelength and voltage in the circuit, with red being the most common at 2v.
• LEDs are also produced in a variety of shapes and sizes to suit its purpose.
LEDs are not like Lasers• Lasers work on a single
colour wavelength which has a greater power output.
• Where as LEDs work on various wavelengths and produce less intense light.
• For example most cheap laser pointers are just LEDS.
• Lasers concentrate on a tiny spot and this enables applications like laser cutting.
LEDs are a POLARISED component• Polarised components must be placed
in circuit in the correct direction of current. If not they will not work.
• LEDs have a positive (Anode) lead and a negative (Cathode) lead and it is important that you known the correct one.
• 3 METHODS TO IDENTIFY THE POLARITY– Longest leg is the positive– The flat side of the LED is the negative side– Inside the LED, the biggest plate is the
negative side