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Electronics devices Fundamentals

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When you are going to start learning the subject Electronics devices, At first sight you need to understand some key concepts and definitions which are explained below. Matter:   Matter is defined as anything that has weight and can occupy space. e.g. our own body, air, water etc. and matter can be found in any one of the three states: Solid, Liquid and Gaseous. Element:  A substance which can not be reduced to a simpler substance by chemical reaction. e.g. copper, gold, silver. Compound:  When two or more elements are combined chemically then the new substance formed is called as compound. Compound can be separated by chemical but not physical means. e.g. salt, water. Atom:  An Atom is the smallest individual particle of an element which retains the characteristics of that element. These atoms of each elements are made up of Electrons, Protons and Neutrons. Electron is having small negative charge of electricity. Proton has positive cha...

Touch Switch using BJT

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This is a simple touch switch circuit built using transistor. In this circuit when a person touches the touch pad provided (or you can have simple wire instead of touch pad) at the base of the NPN transistor and also to the positive of 5V battery then his/her skin acts as a resistor and this closes the circuit and at the same time the transistor turns on and hence the LED connected there glows. Here I have given Proteus demonstration of the same. When no one touches the pad LED is not ON is shown below. When someone touches the pad then the LED glows and is shown below.