PRACTICAL ELECTRONICS MASTERCLASS (Mr Bell)
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
Solder Red LEDs + ANODE SIDE - CATHODE SIDE
Push LED right down Bend legs to help keep LEDs in place