TREE

A photo diode is a PN junction or PIN structure that when light reaches the junction, it excites an electron thereby creating a free electron positively charged. This mechanism is also known as the photoelectric effect, common in transistors, diodes and ICs are made ​​of semiconductors, and contain PN junctions. Almost all of the potentially active constituents are a photo diode and may be used as a photo sensor. The PN junction needs to be exposed to light, so to use a semiconductor diode as a light bulb must have a transparent glass, these diodes with  these characteristics can be used to measure the light intensity.  Circuit diagram of a light intensity meter with diode.   a test circuit diode light sensor List of components: D1 1n148 or any other photo-sensitive element T1, T2 BC548 or similar C1 680n R1 2M Above this circuit that is very popular, it works with LEDs, photodiodes and photo-resistors. V is a voltmeter which can be a multimeter.

Hi…. friends . I am again here with some discussion on Light Emitting Diodes (LEDs) So in this article we will discuss about function and uses of LED . LED are most basic electronic component to be used in almost all the electronic circuit in different forms. If you are going to start with electronics you must have proper knowledge of using LEDs efficiently. INTRODUCTION ( FUNCTION AND CONNECTION) LEDs are unidirectional devices like diode and works only in forward bias condition and emits light when a power supply is connected across the terminal of LED. There are two terminal in simple LED ( some special LEDs contain more than two terminals).As shown in figure below these two terminal are termed as anode ( represented with a or +) and cathode (represented with k (not c) or -). These two terminals must be connected correct way round as a to positive and k to negative terminal of supply. You can determine ANODE and CATHODE by checking the LED as the larger lead is anode and shorter...