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Introduction
A stream of charged particles, such as electrons or ions, travelling through an electrical conductor or space is known as an electric current. It’s the net rate of electric charge flow through a surface or into a control volume.
Charge carriers are the moving particles, and depending on the conductor, they can be one of several types of particles. Electrons flowing through a wire are commonly used as charge carriers in electric circuits. They can be electrons or holes in semiconductors. Ions carry charge in an electrolyte, while ions and electrons carry charge in plasma, an ionised gas.
Electric Current
Magnetic fields are created by electric currents and are used in motors, generators, inductors, and transformers. They cause Joule heating in conventional conductors, which produces light in incandescent light bulbs. Electromagnetic waves are produced by time-varying currents and are utilised to broadcast information in telecommunications.
The ampere, or amp, is the SI unit of electric current, which is defined as the passage of electric charge across a surface at a rate of one coulomb per second.
The rate of charge flow in a conductor is defined as electric current.
Let’s say that q+ represents the net positive charge travelling through the surface in the given time interval, and q– represents the net negative charge passing through the surface in the same time interval. The net charge travelling across this surface in this interval will be, in this situation.
Electric current in Conductors
If an electric field is applied to an electric charge, the charge begins to move as a result of the force, and the movement of these charges forms the electric current. The atoms in a solid conductor are strongly connected to one another, and nearly all of the electrons are bound to the atoms.
Some electrons, which are unattached to any atom, are able to flow freely throughout the substance. These electrons move in random directions when no electric field is applied. There is no favoured direction for electron velocities at any particular time.
This indicates that the amount of electrons moving in any direction is equal to the number of electrons moving in the opposite direction on average. As a result, no net electric current will exist.
Ohm’s Law
According to Ohm’s law, the current flowing through a conductor between two points is proportional to the voltage across the conductor. When the proportionality constant, resistance, is added, the conventional mathematical equation that expresses this relationship arises:
Here I is the current in ampere
V is voltage measured across conductors
R is the resistance.
Ohm’s law, with some modifications, also applies to alternating-current circuits, where the voltage-current relationship is more complicated than for direct currents. Because the current varies, different forms of resistance to the current, known as reactance, emerge in addition to resistance. Impedance, or Z, is the result of combining resistance and reactance.
Ohm’s law applies in an alternating current circuit when the impedance, which is equivalent to the voltage to current ratio, is constant, which is a common occurrence. V/I=Z.
Ohm’s Law Formula
Since we know that:
Voltage=Current×Resistance
V=I×R
V= voltage
I= Current and
R= Resistance
The SI unit of Resistance is ohms and denoted by ‘Ω’.
Application of Ohm’s Law
When the other two values are known, Ohm’s law can be used to determine the voltage, current, impedance, or resistance of a linear electric circuit. It also improves power calculations.
Current Voltage Relationship
Because the ratio V / I remains constant for a given resistance while establishing the current-voltage relationship, a graph of the potential difference (V) and current (I) must be a straight line.
It is the constant ratio which determines the unknown values of resistance
Limitation of Ohm’s Law
- The law of Ohm does not apply to unilateral networks. The current can only flow in one direction in unilateral networks. Diodes, transistors, and other electronic components are used in these types of networks.
- Non-linear elements are also exempt from Ohm’s law. Non-linear elements have current that is not proportional to the applied voltage, which means that the resistance value of those elements varies depending on the voltage and current. The thyristor is an example of a non-linear element.
Conclusion
In this article we have studied about Electric current and about ohm’s Law. Electric currents flow through the equipment we use on a daily basis. Electric equipment that have electric currents flowing through them include torches, lights, fans, heaters, and so on. Assume that charges are flowing in a horizontal path, and that a small section of the surface is held normal to the direction of charge flow. Assume that both positive and negative charges pass through this area.
The charge travelling through the surface can be separated into two portions in a particular time interval “t” and positive charges and negative charges.
