Author: admin
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How to measure current
The instrument used to measure current is called ampere meter or ammeter. � Steps for current measurement Connect a small light bulb to a dry cell. Measure current that passes through light bulb by connecting positive terminal (+) of ammeter to negative terminal (-) of a dry cell (see figure) � Safety instructions for current measurement; 1. Estimate…
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What is resistance?
Electrons move through a conductor when electric current flows. All materials impede flow of electric current to some extent. This characteristic is called resistance. Resistance increases with an increase of length or decrease of cross-section of a material. The unit of measurement for resistance is ohms and its symbol is the Greek letter omega (Ω). The resistance of…
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What is voltage?
Electric current is flow of electrons in a conductor. The force required to make current flow through a conductor is called voltage and potential is the other term of voltage. For example, the first element has more positive charges, so it has higher potential. On the other hand, the second element has charges that are more negative so it…
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What is Current?
An electrical phenomenon is caused by flow of free electrons from one atom to another. The characteristics of current electricity are opposite to those of static electricity.Wires are made up of conductors such as copper or aluminum. Atoms of metal are made up of free electrons, which freely move from one atom to the next. If an…
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What is Electricity?
Any appliances that we use in our daily lives such as household appliances, office equipments and industrial equipments, almost all of those things take electricity. Therefore, we should understand electricity.The first question that we will find out the answer is “where does electricity come from?“ All matters are made up of atoms. Then ask the…
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Magnetism in Practice
Magnetism plays an important role in Electrical and Electronic Engineering because without it components such as relays, solenoids, inductors, chokes, coils, loudspeakers, motors, generators, transformers, and electricity meters would not work! Electromagnetism is the relationship between electricity and magnetism, and it’s the foundation of electric motors, as well as generators and transformers. Michael Faraday discovered…
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Properties of Magnets
Magnets strongly attract objects that contain iron, steel, nickel, or cobalt. Magnets also attract or repel (push away) other hard magnets. This happens because every magnet has two opposite poles, or ends: a north pole and a south pole. North poles attract the south poles of other magnets, but they repel other north poles. Likewise, south…
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Types of Magnetism
Diamagnetism This appears in all materials. Diamagnetism is the inclination for a material to oppose an applied magnetic field, therefore repelling it. However, in a material with paramagnetic properties (that is, with a tendency to enhance an external magnetic field), the paramagnetic behaviour dominates. Diamagnetic behaviour is observed only in a purely diamagnetic material, such as…
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Hard and Soft Magnets
Because of the way their electrons are arranged, the metals iron, steel, nickel, and cobalt make good magnets. Once these metals become magnets, they can stay magnets forever. Then they are called hard magnets. But these metals and others can also act like magnets temporarily, after they have been near a hard magnet. Then they are…
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The History of Magnetism
First, let’s get into the history of magnetism and how it appeared in the ancient world. Magnetism was first discovered when people noticed that lodestones, naturally magnetized pieces of the mineral magnetite, could attract iron. The word magnet comes from the Greek term magnētis lithos, or the Magnesian stone, lodestone. A lodestone is a naturally…