What is Current Electricity? Current or dynamic electricity is defined as an electrical charge in motion. It consists of a flow of negatively charged electrons from atom to atom through a conductor in an electrical circuit. The external force that causes the electron current flow of electric charge is called the electromotive force (emf) or voltage.
The electromotive force (emf) or voltage, which is explained by Ohm law, is created by a battery which consists of one positively charged and one negatively charged terminal. The negative terminal has an excess of electrons while the positive terminal has a deficiency of electrons. When a conductor, in this case an electric light bulb, is connected to the two terminals of the battery, a flow of electrons occurs and produces maganetic fields and an electric field. The positive terminal of the battery has a shortage of electrons and thus attracts electrons from the conductor. The negative terminal has an excess of free electrons to move, which repels electrons into the conductor.
Although "static" and "current" electricity may seem different, they are really the same—both consist of electrical charges. Static electricity consists of electrons at rest on an insulated object and does little work. CE charge flows and does useful work. When static electricity is discharged, it is no longer static electricity—it is current electricity.
CE may also be classified as direct current or alternating current based upon the voltage source. Direct current voltage produces a constant flow of electrons in one direction only. Alternating current voltage produces a flow of positive and negative charge electrons both in direction and in magnitude. A battery is a common dc voltage source, while an electrical wall outlet is the most common ac voltage source (Figure 1).
Polarity identification (+ or -) and magnetic fields are one way to distinguish a voltage source. Polarity can be identified on direct current circuits, but on alternatrng conventional current circuits the current continuously reverses direction; therefore, the polarity cannot be identified. Also, it is important to know whether an electrical energy source produces alternating current or direct current. Many control and load components are designed to operate with a specific type of current. Operating the components with the wrong type of current or DC polarity can result in improper operation and/or permanent damage to the component.
Fig. 1. Current Electricity. Electrical charge in motion.
This 100+ page e-book is a great guide for those who have a basic interest in the field of electricity. This well-illustrated e-book, coupled with some basic knowledge of electricity, will give you a broad theoretical background in this fundamental subject.CONTENTS