PRACTICAL ELECTRONICSMASTERCLASS

(Mr Bell)

1

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

No cross connections of solder