This document discusses the history and characteristics of alternating current (AC). It explains that AC electricity is generated by an AC electric generator and flows first in one direction and then the other, unlike direct current. Some key advantages of AC are that it can be transformed between voltages and controlled by various circuit components. The document also covers concepts such as reactance, impedance, and phase relationships in AC circuits. It describes how AC behaves differently than DC in capacitors and inductors due to the changing current.

1. Alper GÜNEREN - 2010512022
Uğur KARAALİ - 2010512026
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2. OBJECTIVES
SHORT HISTORY
GENERATION
CIRCUITS
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3. HISTORY OF ALTERNATING CURRENT
William Stanley, Jr. designed one of the first practical devices
to transfer AC power efficiently between isolated circuits.
The AC power system used today developed rapidly after 1886,
and included contributions by Nikola Tesla and Carl Wilhelm Siemens.
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4. WHAT IS ALTERNATING CURRENT ?
 Alternating current electricity is the type of electricity commonly used
in homes and businesses throughout the world.
 AC electricity is created by an AC electric generator, which determines
the frequency.
 An AC waveform can be sinusoidal, square, or sawtooth-shaped.
Some AC waveforms are irregular or complicated.
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5. Alternating current flows first in one direction and then in the other
direction.
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6. ADVANTAGES
 The single greatest advantage of alternating current is that AC current
can be transformed and DC current cannot be transformed.
 It can be controlled by a wide range of components
eg.resistors,capacitors and inductors.
 This allows high-voltage electrical power to be distributed with smaller
wires and lower amperage.
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7. HOW TO GENERATED ?
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8. DIRECT ALTERNATING
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9. RMS VALUES
 Since voltage and current are always changing we need some way of
averaging out their effect.
 We use r.m.s values (root-mean-square)
 The r.m.s values are the DC values which give the same average
power output
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10. ALTERNATING CURRENT 10

11. AC IN CAPACITORS
In an AC circuit, the current can continue to flow, as the plates
become alternately charged positively and negatively
For both AC and DC circuits, the voltage across the resistor is
related to the current by V=I.R
A similar relationship exists for a capacitor:
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12. REACTANCE
 Reactance is a measure of how a capacitor can limit alternating
current.
 It is similar to resistance but differs in that it is dependent on the
frequency of the ac supply.
 It also depends on the size of the capacitor.
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13. IMPEDANCE
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14. AC IN INDUCTORS
.In an AC circuit, the current is always changing so the inductor is always producing an
opposing voltage so is always limiting the amount of current that can flow
For both AC and DC circuits, the voltage across the resistor is related to the current by V=IR
A similar relationship exists for an inductor
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15. REACTANCE
 It measures how well an inductor can limit alternating current
 It depends on the frequency of the ac supply.
 It depends on the size of the inductor
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16. IMPEDANCE
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17. PHASE RELATIONSHIP
The current in the circuit will always be in phase with VR
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18. The voltage phasors are not necessarily the same size, but are always
90°out of phase.
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19. Again the voltages may be different sizes but will always be 90° out of
phase
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20. RLC CIRCUITS
The supply voltage is now found
by adding all 3 phasors together.
(VL and VC are combined into
one first)
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21. RESONANCE
At resonance, VL=VC and they cancel each
other out. So VS=VR and if VR is at max then
I is at max.
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22. REFERENCES
• http://www.teachersdomain.org
• http://www.peetvs.co.za
• http://www.sjsu.edu
• http://www.youtube.com
• http://www.wikipedia.com
• http://www.upscale.utoronto.ca
• NCEA A.S 3.6 Text Chapters 18-19
• Yrd. Doç. Dr. Levent Çetin/ alternatif akım
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23. THANKS FOR LISTENING...
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