this contant is physics related.Here AC current explain on the purpose of presentation with some equation and circuit diagram.i thaink it wiil be very effective for the students.

1. Wellcome toWellcome to
Our PresenntationOur Presenntation
OnOn
Alternating CurrentsAlternating Currents

2. Group MembersGroup Members
 Saiful Islam ID:131-15-2516Saiful Islam ID:131-15-2516
Md. Jahirul Shahed ID:131-15-2479Md. Jahirul Shahed ID:131-15-2479
 Saiful Islam ID:131-15-2516Saiful Islam ID:131-15-2516
Md. Jahirul Shahed ID:131-15-2479Md. Jahirul Shahed ID:131-15-2479

3. Alternating CurrentsAlternating Currents
AnAn alternating currentalternating current such as that producedsuch as that produced
by a generator has no direction in the senseby a generator has no direction in the sense
that direct current has. The magnitudes varythat direct current has. The magnitudes vary
sinusoidallysinusoidally with time as given by:with time as given by:
AnAn alternating currentalternating current such as that producedsuch as that produced
by a generator has no direction in the senseby a generator has no direction in the sense
that direct current has. The magnitudes varythat direct current has. The magnitudes vary
sinusoidallysinusoidally with time as given by:with time as given by:
Emax
iimaxmax
time, tE = Emax sin θ
i = imax sin θ
AC-voltage
and current

4. Alternating CurrentAlternating Current
Alternating currentAlternating current flows first in one direction and thenflows first in one direction and then
in the other direction.in the other direction.

5. RMS VALUESRMS VALUES
ALTERNATING CURRENT 5
 Since voltage and current are always changing we needSince voltage and current are always changing we need
some way of averaging out their effect.some way of averaging out their effect.
 We use r.m.s values (root-mean-square)We use r.m.s values (root-mean-square)
 The r.m.s values are the DC values which give the sameThe r.m.s values are the DC values which give the same
average power outputaverage power output

6. RMS VALUESRMS VALUES EQUATIONEQUATION
ALTERNATING CURRENT 6

7. Pure Resistance in AC CircuitsPure Resistance in AC Circuits
A
a.c. Source
R
V
Voltage and current are in phase, and Ohm’sVoltage and current are in phase, and Ohm’s
law applies for effective currents and voltages.law applies for effective currents and voltages.
Voltage and current are in phase, and Ohm’sVoltage and current are in phase, and Ohm’s
law applies for effective currents and voltages.law applies for effective currents and voltages.
I=Io.e^iwt
Vmax
iimaxmax
Voltage
Current

8. A Pure Inductor in AC CircuitA Pure Inductor in AC Circuit
A
L
V
a.c.
Vmax
iimaxmax
Voltage
Current
The voltage peaks 90The voltage peaks 9000
before the current peaks.before the current peaks.
One builds as the other falls and vice versa.One builds as the other falls and vice versa.
I=Io.e^i(wt-90)I=Io.e^i(wt-90)
The voltage peaks 90The voltage peaks 9000
before the current peaks.before the current peaks.
One builds as the other falls and vice versa.One builds as the other falls and vice versa.
I=Io.e^i(wt-90)I=Io.e^i(wt-90)

9. Inductive RInductive Reactanceeactance
ALTERNATING CURRENT 9
 It measures how well an inductor can limit alternatingIt measures how well an inductor can limit alternating
currentcurrent
 It depends on the frequency of the ac supply.It depends on the frequency of the ac supply.
 It depends on the size of the inductorIt depends on the size of the inductor

10. A Pure Capacitor in ACA Pure Capacitor in AC
CircuitCircuit
Vmax
iimaxmax
Voltage
CurrentA V
a.c.
C
The voltage peaks 90The voltage peaks 9000
afterafter the current peaks.the current peaks.
One builds as the other falls and vice versa.One builds as the other falls and vice versa.
I=Io.e^i(wt+90).I=Io.e^i(wt+90).
The voltage peaks 90The voltage peaks 9000
afterafter the current peaks.the current peaks.
One builds as the other falls and vice versa.One builds as the other falls and vice versa.
I=Io.e^i(wt+90).I=Io.e^i(wt+90).

11. Capacitive RCapacitive Reactanceeactance
ALTERNATING CURRENT 11
 Reactance is a measure of how a capacitor can limitReactance is a measure of how a capacitor can limit
alternating currentalternating current..
 It isIt is similarsimilar to resistance but differs in that it is dependentto resistance but differs in that it is dependent
on the frequency of the ac supply.on the frequency of the ac supply.
 It also depends on the size of the capacitor.It also depends on the size of the capacitor.

12. Series LRC CircuitsSeries LRC Circuits
L
VR VC
CR
a.c.
VL
VT
A
Series ac circuit
Consider anConsider an inductorinductor LL,, aa capacitorcapacitor CC,, andand
aa resistorresistor RR all connected inall connected in seriesseries withwith anan
ac sourceac source..
I=Io(e^i(wt-angle).I=Io(e^i(wt-angle).
Consider anConsider an inductorinductor LL,, aa capacitorcapacitor CC,, andand
aa resistorresistor RR all connected inall connected in seriesseries withwith anan
ac sourceac source..
I=Io(e^i(wt-angle).I=Io(e^i(wt-angle).

13. Phase in a Series AC CircuitPhase in a Series AC Circuit
The voltageThe voltage leadsleads current in an inductor andcurrent in an inductor and lagslags
current in a capacitor.current in a capacitor. In phaseIn phase for resistancefor resistance RR..
θ
450
900
1350
1800
2700
3600
V V = Vmax sin θ
VR
VC
VL
RotatingRotating phasor diagramphasor diagram generates voltagegenerates voltage
waves for each elementwaves for each element RR,, LL, and, and CC showingshowing
phase relations. Currentphase relations. Current ii is alwaysis always in phasein phase withwith
VVR.R.

14. AAdvantagesdvantages
ALTERNATING CURRENT 14
 The single greatest advantage of alternating current is thatThe single greatest advantage of alternating current is that
AC current can be transformed and DC current cannot beAC current can be transformed and DC current cannot be
transformed.transformed.
 It can be controlled by a wide range of componentsIt can be controlled by a wide range of components
eg.eg.resistors,capacitors and inductors.resistors,capacitors and inductors.
 This allows high-voltage electrical power to be distributedThis allows high-voltage electrical power to be distributed
with smaller wires and lower amperage.with smaller wires and lower amperage.

15. RReferenceseferences
ALTERNATING CURRENT 15
• http://www.teachersdomain.orghttp://www.teachersdomain.org
• http://www.peetvs.co.zahttp://www.peetvs.co.za
• http://http://www.sjsu.eduwww.sjsu.edu
• http://www.youtube.comhttp://www.youtube.com
• http://http://www.wikipedia.comwww.wikipedia.com
• http://www.upscale.utoronto.cahttp://www.upscale.utoronto.ca
• NCEA A.S 3.6 Text Chapters 18-19NCEA A.S 3.6 Text Chapters 18-19
• Yrd. Doç. Dr. Levent Çetin/ alternatif akımYrd. Doç. Dr. Levent Çetin/ alternatif akım

16. THANKSTHANKS
TOTO
ALLALL