LED CONNECTION

•Series Connection

Requires more voltageThe supply voltage

should be the sum of the rated voltage required for LED

•Parallel Connection

Requires more currentThe supply current

should be the sum of the rated current requirement for LED

SEVEN SEGMENT LED

Each of the seven segment ( and the decimal point) in a given digit contains an individual LED.

When a suitable voltage is applied to a given segment LED, current flows through and illuminates that segment LED.

ApplicationNumeric displayClocksCalculatorsScoreboard

INFRARED LED

Infrared is light that has a range of wavelengths greater than the visible light.

Therefore, this LED can produce light but invisible light.

ApplicationTV remote control transmitter

Security system

PHOTO DIODE

Photo diode is a pn junction device that operates in reverse bias.

The photodiode has a small transparent window that allows light to strike the pn junction

Application

Receiver of the infrared LED

CURRENT REGULATOR DIODE

This diode maintain a constant current

The current regulator diode operates in forward bias and the forward current becomes a specified constant value at forward voltage ranging from about 1.5V to about 6V

SCHOTTKY DIODE

Used primarily in high-frequency and fast switching applications

Formed by joining a doped semiconductor region with metal such as gold, silver, or platinum

PIN DIODE

Consist of heavily doped p and n regions separated by an intrinsic region

When in reverse-bias, the pin diode acts like a nearly constant capacitance

When forward-bias, it acts like a current-controlled variable resistance

Application Used as a DC-controlled microwave

switch operated by rapid changes in bias or as a modulating devise that takes advantage of the variable forward resistance characteristic

Used in attenuator applications because its resistance can be controlled by the amount of current

Used as photo detectors in fiber-optic system

TUNNEL DIODE

Exhibits a special characteristics known as negative resistance

This features makes it useful in oscillator and microwave amplifier application

Constructed with germanium or gallium arsenide by doping the p and n regions much more heavily than in a conventional rectifier diode

LASER DIODE

LASER (Light Amplification by Stimulated Emission of Radiation)

LASER light is monochromatic

ApplicationPick up system of compact disk player

Printers and fiber communication