When two objects charged with unlike potentials are connected together by a conducting wire, charges flow from one body to another body. The charge flows from higher potential to the lower potential until the potential of the objects become equal. The electric current during a conductor across an area held perpendicular to the direction of flow of charge is defined because the amount of charge flowing across that area per unit time. The S.I. unit of electric current is ampere and 1 ampere is equal to 1 coulomb per second.
A German physicist George Simon ohm derived the relation between current and potential difference. This relationship was further known as ohm’s law.
This law is stated as follows:
The current flowing through a conductor is directly proportional to the potential difference applied across the ends, provided the temperature and physical conditions remain constant.
V = IR
I: Electric Current
R: Resistance of the material
Where ‘R’ is proportionality constant called resistance. Its value is independent of potential difference and current. It depends on the nature of the conductor, length, area of cross-section and physical condition like temperature.
Limitations of ohms law:
Many substances follow ohms law but it is not fundamental law.
On the basis of these conductors are divided into ohmic conductors and non-ohmic conductors.
Electric Current Types
1. AC (Alternating Current)
The value of AC current in one direction increases from ZERO to Maximum and falls right down to ZERO then within the other way, it increases from ZERO to Maximum again and comes back to ZERO. Electrical current whose direction and value keeps changing is understood as AC (AC).
2. DC (Direct Current )
DC or DC is that the flow of electrical charge in one direction. this is often called the unidirectional flow of electrical charge. DC current is produced by devices sort of a battery, thermocouple, photovoltaic cell, dynamo, etc. DC current is additionally called galvanic current.