Electric current

INTRODUCTION

· Electricity can be represent by the charge. If body is charged by friction and the charge is stationary then the electricity is called frictional electricity. 
· If charge is moving from one place to another through the conductor it is called current electricity.
 

ELECTRICITY CIRCUITS

· The path of flow of electricity from one terminal of the cell and returning to the other is called and electrical circuit. 
(a) Open Electric Circuit : An electric circuit through which no electric current flows is known as open electric circuit. The electric circuit or it the connecting wires break from any point.
(b) Closed Circuit : An electric circuit through which electric current flows continuously is known as closed circuit.
· For flow of electricity, the circuit must be made of conductors, insulators in the path of electrical circuits makes the circuit incomplete.
 
ELECTRICAL CELLS
 
Electrical cells are the sources of electric current. 
Types of electrical cell : (i) primary
                                        (ii) secondary
 
(i) Primary Cells :      The cells which cannot be charged again and again are known as primary cells.
                                     Eg : Voltaic, Daniel, laclanche and dry cells. 
 
(ii) Secondary Cells : The cells which can be charged again and again are known as secondary cells. 
                                     Eg : Edison cell, lead - acid accumulator.
                                       Note : Combination of cell is known as battery.
 
 
CIRCUIT DIAGRAM AND CIRCUIT SYMBOLS
 
             Scientists use certain symbols to draw electrical circuits. An electrical circuit drawn using these symbols is called a circuit diagram.
            The symbols used to indicate different components are called circuit symbols. Figure shows some components and their circuit symbols.
 
An electrical circuit in symbols :