Solar Cell

The solar cell is a type of cell that transforms the light energy into electricity. The principle of solar cell is like photovoltaic action. This type of action occurs in all semiconductors, which are basically formed to...

DC Network

 1. Define electric current? Ans: The valence electrons in different atoms of a material are free to move from one point to other. When an electron field is applied to a conductor the motion of electrons...

Uni-Junction Transistor (UJT)

A Uni-junction transistor (UJT) is a switching device.It switches from blocking to conducting state when the applied voltage reaches a critical value. It is a bar of high resistivity semiconductor with ohmic contacts at each end....

Light Emitting Diode (LED)

Light energy can excite an electron into the conduction band. On the other band, when recombination takes place energy is released. In a semiconductor with an indirect band gap, e.g, silicon,germanium etc. recombination releases heat to...

Energy Levels

Energy Levels: An atom consist of positively charged nucleus which contains almost all it's mass. Surrounding this nucleus are negatively charged electrons moving about in closed orbit. While in states corresponding to these discrete energies, electrons...

Common Emitter (CE) Connection Of Transistor

The most transistor circuits operate with the emitter terminal as common to the input and output circuits. This is known as CE connection and is shown Figure-1. In this connection the left hand loop is the...

Basic Concepts of Amplifier CKT

Introduction: The collective abbreviation of the two English words 'transfer' and 'resistor' is the transistor. It basically works on the Resistance Transfer rule. The transistor is called a current driven device. And this current is transfer...

Bank Vault Security System with Password Protection (2nd Part)

Motor Driver Circuit (H-Bridge): Two H-bridge motor driver circuits are used for driving the motors of the Door of the bank vault. One is used to rotate the door & another one is used to open/close...

Bank Vault Security System with Password Protection (1st Part)

Background: The main factor in bank vault is considered on the security system but most of the times it is based on human supportive surveillance system. But we know, that is not full proof & enough...