Alternating current

Alper GÜNEREN - 2010512022Uğur KARAALİ - 2010512026

1

OBJECTIVES

SHORT HISTORY

GENERATION

CIRCUITS

2ALTERNATING CURRENT

HISTORY OF ALTERNATING CURRENT

ALTERNATING CURRENT 3

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.

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.


Alternating current flows first in one direction and then in the other

direction.

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.

HOW TO GENERATED ?


DIRECT ALTERNATING


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


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:

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.

IMPEDANCE


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

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

IMPEDANCE


PHASE RELATIONSHIP


The current in the circuit will always be in phase with VR


The voltage phasors are not necessarily the same size, but are always

90°out of phase.


Again the voltages may be different sizes but will always be 90° out of

phase

RLC CIRCUITS


The supply voltage is now found

by adding all 3 phasors together.

(VL and VC are combined into

one first)

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.

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

THANKS FOR LISTENING...

ALTERNATING CURRENT END

Education

Alternating current