Describe the difference between direct and alternating current.
Particulars
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Direct Current
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Alternating Current
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1. Waveform
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2. Definition
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It is the current whose magnitude and direction do not change with respect to time.
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It is the current whose magnitude and direction continuously changes with respect to time.
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3. Use of transformer
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Not possible
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Possible
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4. Design of machines
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Complicated
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Simple
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5. Frequency
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Zero
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It is 50 Hz or 60 Hz depending upon country.
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6. Obtained from
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Battery, Cell and DC Generator
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Alternator
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7. Passive parameters
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Resistance only
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Resistance, Inductance, Capacitance.
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8. Applications
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DC machines, HVDC system, electroplating, Battery charging, Traction.
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AC machines, Domestic and industrial supply.
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Point
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AC Supply
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DC Supply
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Amount of energy that can be carried
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Safe to transfer over longer city distances and can provide more power.
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Voltage of DC cannot travel very far until it begins to lose energy.
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Cause of the direction of flow of electrons
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Rotating magnet along the wire.
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Steady magnetism along the wire.
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Frequency
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The frequency of alternating current is 50Hz or 60Hz depending upon the country.
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The frequency of direct current is zero.
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Direction
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It reverses its direction while flowing in a circuit.
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It flows in one direction in the circuit.
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Current
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It is the current of magnitude varying with time
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It is the current of constant magnitude.
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Flow of Electrons
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Electrons keep switching directions - forward and backward.
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Electrons move steadily in one direction or 'forward'.
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Obtained from
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A.C Generator and mains.
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Cell or Battery.
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Passive Parameters
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Impedance.
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Resistance only
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Types
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Sinusoidal, Trapezoidal, Triangular, Square.
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Pure and pulsating.
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