The bidirectionality is caused by a sinusoidally varying current and voltage that reverse directions, creating a periodic back and forth motion for the current. The electrical outlets at our home and industries are supplied with alternating current. When two bodies at different potentials are linked with a wire, free electrons stream from Point 1 to Point 2, until both the objects reach the same potential, after which the current stops flowing.

Metals

A battery is a common DC voltage source, while an electrical wall outlet is the most common AC voltage source (Figure 1). Electrons move toward a positive terminal in an electric circuit. The electron flow, or moving charge, is therefore away from the negative terminal.

unit of electric current

The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage. The I symbol was used by André-Marie Ampère, after whom the unit of electric current is named. The notation traveled from France to Great Britain, where it became standard, although at least one journal did not change from using C to I until 1896.

0Types of Electric Current

• It is produced when certain objects are rubbed against each other resulting in charge transfer.
• Current electricity is essential for the operation of many devices, including lights, appliances, and electronic gadgets.
• The relationship between resistance, current, and voltage (another part of the circuit) is shown by Ohm’s law.
• When these charges stay at a specific area or point they are static (not moving) in nature and those which continuously flow from one point to another are dynamic.
• Electric current is measured using an ammeter, which is connected in series with the circuit.
• Domestic DC installations usually have different types of sockets, connectors, switches, and fixtures from those suitable for alternating current.

Electrical current is a measure of the amount of electrical charge transferred per unit of time. It represents the flow of electrons through a conductive material, such as a metal wire. Current electricity is created when a difference in electrical potential, or voltage, is applied to a circuit.

In this first volume, we break down the essential concepts in a straightforward manner, covering key topics such as Ohm’s Law, electrical circuits, resistance, power, and energy. Through simple explanations, practical examples, and visual aids, this handbook offers a comprehensive understanding of how electricity works and its fundamental properties. This principle forms the basis for the operation of electric motors, where current-carrying conductors are intentionally placed in magnetic fields to produce rotational motion. It states that the heat produced in a conductor is directly proportional to the square of the current, the resistance of the conductor, and the time for which the current flows. When the current flows in positive and negative directions alternatively in a cycle, it is called alternating or AC.

It is one of the important discoveries that helped us transform our way of living. From the time we wake up till the time we sleep at night, our life is dependent on electricity. From the basic bread toaster and baking oven to the commonly used television all require electric current to operate.

Measurement

We can find the direction of the magnetic field using the right-hand rule. In this rule, if you hold the conductor with your right hand so that your thumb points in the direction of current flow, the curl of your fingers will indicate the circular path of the magnetic field lines. The direction of electric current is opposite to that of electrons. The conventional direction of the current is from the higher to the lower potential point. This is why circuit diagrams often show arrows pointing in the opposite direction of actual electron movement. Electric current is the ratio of charge transferred in a given period.

The centimetre–gram–second units of current is the electrostatic unit of charge (esu) per second. Current in gases and liquids generally consists of a flow of positive ions in one direction together with a flow of negative ions in the opposite direction. To treat the overall effect of the current, its direction is usually taken to be that of the positive charge carrier. A current of negative charge moving in the opposite direction is equivalent to a positive charge of the same magnitude moving in the conventional direction and must be included as a contribution to the total current. Current in semiconductors consists of the motion of holes in the conventional direction and electrons in the opposite direction. The current electricity that is bidirectional and keeps changing the direction of the charge flow is known as alternating current.

Definition and Concept of Electric Charge:

Whether you are new to the subject or looking to refresh your knowledge, Basic Electricity Handbook, Vol. 1 provides a solid foundation for further study or practical application in electrical engineering, technology, and various industries. This guide is an indispensable resource for building confidence and competence in working with electricity, helping you unlock the power that drives the modern world. It also flows in biological systems, such as ion currents in nerve cells and plasma currents in scientific and industrial applications.

• It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
• In a conductive material, the moving charged particles that constitute the electric current are called charge carriers.
• The conventional direction of the current is from the higher to the lower potential point.
• The amount of water flow is proportional to the pressure placed on the end.
• Switches are used to turn current off (or on) almost instantly, as soon as the charge lacks a place to go (remember, current only moves when there’s a full circuit) the current stops.
• Electricity, with its origins in the fundamental property of electric charge, has transformed from a natural curiosity to a vital force driving modern civilization.

These charges remain static until they are grounded, or discharged. Basically, the phenomenon of static electricity arises when the positive and negative charges are separated. Since a “perfect vacuum” contains no charged particles, it normally behaves as a perfect insulator. However, metal electrode surfaces can cause a region of the vacuum to become conductive by injecting free electrons or ions through either field electron emission or thermionic emission. Externally heated electrodes are often used to generate an electron cloud as in the filament or indirectly heated cathode of vacuum tubes. Cold electrodes can also spontaneously produce electron clouds via thermionic emission when small incandescent regions (called cathode spots or anode spots) are formed.

direction

Voltage creates pressure on the electrons, which channelises them to flow in a single direction. In a DC circuit, a power source (e.g. a battery, capacitor, etc.) has a positive and negative terminal, and likewise, the load also has a positive and negative terminal. To complete the circuit, positive charges need to flow from the power source to the load. The charges will then return to the negative terminal of the load, which will then flow back to the negative terminal of the battery, completing the circuit. If either the positive or negative terminal is disconnected, the circuit will not be complete and the charges will not flow.

In metallic solids, electric charge flows by means of electrons, from lower to higher electrical potential. In other media, any stream of charged objects (ions, for example) may constitute an electric current. To current electricity definition provide a definition of current independent of the type of charge carriers, conventional current is defined as moving in the same direction as the positive charge flow. So, in metals where the charge carriers (electrons) are negative, conventional current is in the opposite direction to the overall electron movement. In conductors where the charge carriers are positive, conventional current is in the same direction as the charge carriers.

It is the name given to the movement of charge or electrons through a material. The term “electricity” is used to refer to the widespread energy flow that powers everything electric. In alternating current (AC, also ac), the movement of electric charge periodically reverses direction.