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Electricity & Megnetism

What is modulation and demodulation

What is modulation? Until the process of superimposing a low frequency (long wave) voice information component on a high frequency (short wave) carrier signal was perfected,the most widely used form of communication was a system based on the transmission of a continuous wave (CW) signal.With this system,the signal was interrupted periodically (Morse code) to produce a coded message.The CW system ...

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How does electric motor works

What is Electric Motor? An electric motor is an electromechanical device that converts electrical energy into mechanical energy.Electrical motors can be run as generators and vice versa, although this is not always practical. The Motor Principle: When a current-carrying conductor is located in an external magnetic field perpendicular to the conductor, the conductor experiences a force perpendicular to itself and ...

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magnets how do they work

What are Magnets? A permanent magnet has a magnetic field surrounding it. A magnet field can be envisioned to consist of lines of force that radiate from the north pole (N) to the south pole (S) and back to the north pole through the magnetic material. A permanent magnet, such as the bar magnet has a magnetic field surrounding it that ...

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What is Transducer

What are transducers? “A transducer is an electronic device that converts energy from one form to another.”Common examples include microphones,loudspeakers,thermometers,position and pressure sensors and antenna.Although not generally thought of as transducers,photocells,LEDs,and even common light bulbs are transducers. Efficiency of transducer: Efficiency is an important consideration in any transducer.Transducer efficiency is defined as:”The ratio of the power output in the desired ...

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How do electromagnetic waves travel

What are Electromagnetic Waves? Electromagnetic waves are defined as:” Waves which requires no medium for transmission and which rapidly propagates through vacuum.”radio waves,television waves,X-rays light rays etc,are the examples of electromagnetic waves. In 1864 British physicist James Clark Maxwell formulated a set of equations known as Maxwell’s equations which explained the various electromagnetic phenomena. According to these equations, a changing ...

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What is difference between step-up and step-down transformers?

“A transformer is an electrical device to change a given alternating emf into a larger or smaller alternating emf.”or “It is a static or stationary piece of apparatus that transfers electric power from one circuit to another having mutual inductance without changing the frequency.”A basic transformer is an electrical device constructed of two coils placed in close proximity to each ...

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Standard resistor values

Carbon resistors are most common in electronic equipment.They consists of a high grade ceramic rod or cone ( called the substrate on which is deposited a thin resistive film of carbon. The numerical value of their resistance is indicated by a colour code which consists of bands of different colors printed on the body of the resistor.The color used in ...

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Describe the structure of an atom

what is Atom? “Atom is the smallest particle of an element that possesses the unique characteristics of that element.”All matter is composed of atoms;all atoms consists of electrons,protons, and neutrons except normal hydrogen,which does not have a neutron.Each element in the periodic table has a unique atomic structure,and all atoms within a given element have the same number of protons.At ...

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Potentiometer as a variable resistor

What is potentiometer? “A potentiometer is a very simple instrument which can measure and compare potential differences accurately”.Potential difference is usually measured by an instrument called a voltmeter. The voltmeter is connected across the two points in circuits between which potential  differance is to be measured. It is necessary that the resistance of the voltmeter be large compared to the ...

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resistor and its types

A resistor is an electrical component with a known specific value of resistance.It is probably the most common component in all kinds of electronic equipment ranging from a small radio to a colour television receiver.As its name suggests ,a resister resists or opposes the flow of current through it.Resistance is necessary for any circuit to do useful work.In fact,without resistance,every ...

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