Current Electricity: Sources and Accessories

Electrical charges that are moving are known as current or dynamic electricity. It is the movement of negatively charged electrons inside an electrical circuit from one conductor to another. Lightning is one observable electric current example in nature, and man-made examples include the passage of conduction electrons in a metal. Electromotive force (emf), often known as voltage, is the outside force that generates the movement of electric charge through electrons.

Current electricity is used for various things, such as starting a car, turning on a light, using an electric stove, and charging a cell phone.

Static Electricity

Static electricity is the discharge of an electrical pulse caused by an imbalance of positive and negative charges within an object.

The short-lived phenomena of lightning demonstrate static electricity. Its generation results from exchanging atomic particles, which also produce short-duration energy.

Electric Current

The term "electric current" describes the direction and amount of electricity flowing across a circuit in an electrical device. It is represented by the letter “I” and measured in amperes (A).

Given by the expression: I = q/T.

Where q is the charge in Coulombs.

T is the time in seconds.

Difference Between Current and Electricity 

The basic difference between current and electricity is that Electricity is a form of energy produced by the movement of electrons. At the same time, The flow of charge per unit of time is referred to as current. A general characteristic of electricity is current, along with voltage and resistance. Thus, cells should be arranged by internal and external resistance to supply maximum current. Therefore, infinite resistance in a resistance box has no current flow in the circuit, implying infinite resistance is introduced.

Types of Current Electricity

Today, two distinct forms of current are frequently used. They are alternating current (abbreviated AC) and direct current (abbreviated DC).

The electrons in a direct current flow in a single direction. An electron flow that only flows in one direction is produced by direct current voltage. In case of alternating current, the polarity(flow direction) keeps changing. The most frequent dc voltage source is a battery, while the most frequent ac voltage source is an electrical wall outlet. 

Source of Electric Current

The  sources of electric current are as follows:

• Electric cell

• Mains 

• Generators

Electric Cell: A device that transforms chemical energy into electrical energy is called an electric cell.

There are two types of electric cells.

(i) Primary Cells

A primary cell or battery must be thrown away after use because it cannot be easily recharged. Dry cells are defined as primary cells that use electrolytes that are enclosed within absorbent material or a separator (i.e., no free or liquid electrolyte). Examples of primary cells are Voltaic, Daniel, and Leclanche.

(ii) Secondary Cells

A secondary cell or battery may be electrically recharged to its initial pre-discharge condition following use by running current through the circuit in the opposite direction from the current during discharge. Lead-acid accumulators, nickel-cadmium (NiCd), nickel metal hydride (NiMH), lithium-ion (Li-ion), and other materials are examples of secondary cells. The lead accumulator refers to a secondary cell because the electrical energy is not produced internally but is stored before coming from an external source.

Leclanche Cells: 

A glass vessel containing an ammonium chloride solution makes up a Leclanche cell. A solution of ammonium chloride serves as an electrolyte. A zinc rod and porous pot holding a carbon rod wrapped in a mixture of manganese dioxide and powdered carbon are included. The carbon and zinc rods function as the corresponding positive and negative electrodes.

Disadvantages:

• There is little energy density.

• Low temperatures result in poor service.

• Has inadequate leakage resistance.

• cannot operate effectively when a high current drain is applied.

• Shelf life could be better.

• With discharge, voltage drops continuously.

Advantages:

• This battery cell is reasonably inexpensive.

• These cells are readily available in various forms, dimensions, and capacities.

• Long-standing customary dependability.

Dry Cells

A dry cell is a machine that uses chemical reactions to produce electricity. The cell pushes the electrons to flow from one end to another when a closed route connects its two electrodes. In a closed circuit, the current moves because of the passage of electrons. The electrons go from one end to the other with the aid of chemical reactions. More electrons flow when two or more cells are coupled correctly and polarised due to the high potential. A battery is a name given to this mixture. A battery can produce various voltages, ranging from 1.5 V (the lowest voltage possible) to 100 V. Using power electronic converters like chopper circuits, even the battery's output DC voltage can be adjusted to various levels.

Working

Reactions between the electrolyte and the electrodes cause the flow of electrons from one electrode to the next. Ionised particles are created when substances like acids dissolve in water. Two types of ionised particles exist. The negative ions are referred to as anions, and the positive ones are called cations. The acids that dissolve in water are referred to as electrolytes.

Advantage

• Dry cells are ideal for powering small electrical gadgets due to their modest size. 

• The electrolyte used in dry cells is not particularly environmentally damaging.

• Dry cells are reasonably priced.

Disadvantages

• The biggest drawback of a dry cell is that it cannot be replenished once it runs out of electricity.

Summary

Electric cells come in a variety; some have a long shelf life, while others can be recharged. Because the battery's self-discharge speeds up in high temperatures, it should be stored in a cool environment. An electric cell is further divided into the primary and secondary cells, depending on whether it is rechargeable.