The document summarizes key concepts about electricity and electrical circuits. It discusses: 1) Direct current (DC) and alternating current (AC), explaining the difference between constant and varying current over time. 2) Transformers, describing how they work by electromagnetic induction to change voltage and current levels while transmitting power. 3) Circuit parameters like voltage, current, resistance and power in AC circuits. Formulas are given relating peak, RMS and average values. 4) Waveforms of voltage, current and power over time in an AC circuit, showing their sinusoidal variation and phase relationship. In 3 sentences or less, the document provides an overview of basic electrical concepts like different current types, transformer

1. SchoolDD.com
17
N S
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2. 17
17.1
F 16 F F F F F
I
I
B B I
I
F (Michael Faraday) F F F F F F
F F F
F F F
17.1.1 F F F
I
e Q
I I
P
F F F F F F
F F F F
F F F F F
P Q( ) F F Q P
Q P F F F P Q F F
F F F F F
F
F F www.schoolDD.com 1

3. 17.1.2 F F F
F F F F
F F 2
1
I
N
N
B2 > B1
. F F F F F = 2- 1
I
I
N
N
B2 < B1
. F F F F = 2- 1
I
F F F
F F
F FF F F F F
F F
= 2 - 1
I I
2
1
= 2 - 1
I I
1
2
F F www.schoolDD.com 2

4. F 1
. .
v v
. . . .
N N S S
. . . .
N N S S
17.1.3 F F
y
Q R
N v I
B S
I B
v
P S
x
F PQRS F F
xy F v F B F
F F PQ RS F F PS
QR F F
F
F F www.schoolDD.com 3

5. 17.1.4 F
F 16 F I1 F F
F B F F .
N I1 F B S N v I S
B B 2
F I1 I2 B
v
. F .
F
I2 . F F F I1
F F F
F (Back emf)
F F
1. F v=0 F F I2 = 0
F F F I1- I2 = I1 F F
2. F I2 F F I1 F
F F I = I1- I2 F F (v ) F I2
F F F (Imin)
3. F F I2 F
F F F F F F
F F F F F F
F F F
F 2
F F 12 F F 10 F
F F8 F F F F
F F www.schoolDD.com 4

6. I1
F F I = I1 I2 I2
= - 12 V M
I
8= -
8=
R=
R = 0.25 Ans
17.2
F F
F F F 2
17.2.1
I
N v I S
B 2
I2 B 0 t
v /4 /2 3 /4
F
F
F F F F F
F
F F F
F F
F F F F
F F F
F F F F
F F F F
F I t F F
(Direct Current D.C )
F F www.schoolDD.com 5

7. 17.2.2
I
N v I S
B 2
I2 B 0 t
v /4 /2 3 /4
F
F F F
2 F F
F F F
(Alternating Current A.C. )
F F F F F F
F F F F
I F FV
0 t 0 t
T/2 T 3T/2 2T T/2 T 3T/2 2T
1 1
T 1 F f F
1 F 50 F (
50 Hz) F 50 1 F F 220 F
N S
F F www.schoolDD.com 6

8. F F F F F F
F F FF
17.2.3 3
2 1
N S
3
F F
3 120° F F F F F
F F F
F F 120° F FF F F
F F F F F F F
F
F FV
t 1
t 2
t 3
F F www.schoolDD.com 7

9. F
C B
220 V
2 1
F F
N S F3
3
D A
E F 220 V
3 220 V
( F BDF F F )
3 F 6 F F
F F F F F F F F F
(N) F F 3 F F F F ( L)
F F 3 4 (L 3 +N1
) F F F F
3 F F F F F F F
F F F F F F 3 F
3 3 F F F
F F 3 F F 3 F F FF
F F F F F
F F
F F
F F F F F F F
F F F F
F F F F F
F
F
F F
F F F F
F F www.schoolDD.com 8

10. W = QV
W = ItV (I = Q/t)
W = I2Rt
P=
P=
P = IV
F 3
F F F 110 F F
F F F 100 F 0.20 F 10 F F F
. 220 F . 220,000 F
F P = 110x103 W , R = 0.20 , t = 10 s
. V= 220 V , W = ?
W = I2Rt ---1
F R, t I P = IV
I= = = 500 A
F I 1 , W = (500)2x0.2x10
W = 500,000 J Ans
. V = 220,000 , W = ?
W = I2Rt ---1
F R, t I P = IV
I= = = 0.5 A
F I 1 , W = (0.5)2x0.2x10
W = 0.5 J Ans
- F F F F F F F
F F F F F
3 F F F
F F F F F F
230,000 F F F F F 69,000 F F F
F F F 220 F F F F F F
F
F F www.schoolDD.com 9

11. 17.3 F (Transformer)
F F
I2
F F I1 F
R E2
E1 N1 N2
I1 I2
N1 N2
F F
F F F F F F F
F F
F
F I1 E1 F F
F F ( I1 F ) F F F
F F E2
I2 F F
= =
V1 V2 F F F
F 2
1. F ( N2 > N1 F E2 > E1 ) N1 N2
2. F ( N2 < N1 F E2 < E1 )
N1 N2
F F F
F F F
F F F F
W1 = W2
F F www.schoolDD.com 10

12. P1 = P2 I1V1 = I2V2
P1 = F
P2 =
(Eddy current)
F F
F F F F
F F F F ( P2 < P 1 )
F F
F F F F F F F F F
F F F
F
1. F F F
2. F F F F F - F F
3. = =
4. F N2 > N1 , E2 > E1
F N2 < N1 , E2 < E1
5. P1 = P2
F 4
F 200 50 F
12 F F 0.5 F F F
F F
I1 = 0.5
I2 = ?
E1 = 12
N1 = 200 N2 = 50
=
E 2 = E1
= 12
F F www.schoolDD.com 11

13. E2 = 3 V = V2
P 1 = P2
I1V1 = I2V2
V1 = E1 , V2 = E2
F F 0.5x12 = I2x2
I2 = 2 A Ans
F 5
F 20 100 F F
F 25 F F F F 20 F F F F
25 F F
E1 = 20 R = 25
N1 = 20 N2 = 100
F F 25 F F F F F F
F F (W/ Q) F F
W = QV
V=
E1 = V1 = 20 V
=
E 2 = E1
= 20
E2 = 100 V
V = IR
I2 =
=
I2 = 4 A Ans
F F www.schoolDD.com 12

14. 17.4 F F
i R
V
AC
i F Fv
Im Vm
0 t 0 t
T/2 T 3T/2 2T T/2 T 3T/2 2T
- Im - Vm
F R F AC ( F ) (i)
F F F F (v) F F F
F F
i = Im sin t =
= = =2 f
v = Vm sin t
i v F F t
Im Vm F F
F
F F F F
v = iR
V m = Im R
(p) F
F F www.schoolDD.com 13

15. p = iv
Pm = Im Vm
F i, F Fv, p t
i,v, p
Pm p p , Pm i v
Vm v
Im
i t
0
- Im T/2 T
- Vm
FF F F F 1 F F F
F
i,v
i +
i = F
=0 ( +,-)
0 t
v - T v = F
=0
p p =
Pm p=iv
p
= ½ ImVm
t = ½ Im(Im R) = ½ ( )Vm
0
T
p = Im2 R =
i v
Im Vm
0 t 0 t
- Im - Vm
i2 v2
Im 2 Vm2
i2 = Im2 /2 v2 = Vm2 /2
t t
0 0
T T
F F www.schoolDD.com 14

16. FF
(i2) = ½ Im2 (v2) = ½ Vm2
F F Irms = = F
Vrms = = F F F
F F
p = = ½ ImVm = x = Irms Vrms
F Irms Vrms F F F F F F F F F
F F F F F F I V
, F F
1. i = Im sin t (Im = )
F F v = Vm sin t (Vm = F F )
2. F F F F (V = IR)
v = iR
Vm = ImR
3. F F (P = IV)
p = iv
Pm = Im Vm
p = = = IrmsVrms
4. F
Irms =
Vrms =
F 6
i t i = 2 sin (314t)
.
.
. F Irms
i = Im sin t
F i = 2 sin (314t )
F F www.schoolDD.com 15

17. 2 F
Im = 2 A Ans
= 314
2 f = 314
f= = 50 Hz Ans
Irms = = = A Ans
F 7
40 F , 220 F F F F 220 F
. F
. F
.
. 40 W , 220 V
i
AC
Vrms = 220
. F R
p = 40 W , Vrms = 220 V
P = IV = V
=
R= =
R = 1210 Ans
. F Im
Irms =
Im = Irms
= Irms
=
=
Im = 0.26 A Ans
F F www.schoolDD.com 16

18. . Pm
Pm = ImVm
= Im( Vrms)
= 0.26( x220)
Pm = 80 W Ans
. p
p =
=
p = 40 W Ans
F 8
F F F F F F F F 220 F F F
F F F 10 F F F
F Vrms = 220 V Irms = 10 mA
Vm Vrms =
Vm = Vrms = x220
Vm = 311 V Ans
Im Irms =
Im = Irms = x10
Im = 14 mA Ans
17.5
C i,v
i
iC iC vC F 90°
0 t
V vC
AC
. F i,v t
F C F F F iC
F F F vC F 90°
F F www.schoolDD.com 17

19. i,v
i L
0 vL t
V
iL
AC
F L F F F F vL F
F iL F 90° .
F R,L,C
p
v = Vm sin t i,v p=iv
Pm
R i = Im sin t Im Vm t t
i v p = iv
Pm = ImVm i v
p = Pm/2
p
C i,v p=iv
v = Vm sin t Pm
Im , Vm i
t t
i v i = Im sin ( t + /2) v
p = iv
i v F
Pm = ImVm/2
p =0
p
L v = Vm sin t i,v p=iv
Pm
i v Im , Vm v t t
i = Im sin ( t - /2)
i
p = iv
Pm = ImVm/2 v i F
p =0
F F www.schoolDD.com 18

20. F
F ( XC ) F F
( XL ) F F F F F
F
F R=
XC =
XL =
F XC XL F FF F f F
C F L F
XC = =
XL = L = 2 f L
f= F ( F )
C= ( )
L= ( )
F 9
F F F F F
F 10 F F F F F F F F
F 8.0 , 12.0 6.0 F F F
F
R C L
i
R,C,L F F F 10 mA F Irms = 10
mA
F Vrms = 8 V
F F www.schoolDD.com 19

21. R R= =
R = 800 Ans
Vrms = 12 V
XC XC = =
XC = 1200 Ans
Vrms = 6 V
XL XL = =
XL = 600 Ans
F 10
50 F F F rms 12 F F rms
F
. F F 10 F
. 33
. 20
. R
f = 50 Hz
Vrms = 12 V
V = IR I=
Irms = =
Irms = 1.2 A Ans
.
C = 33 F
f = 50 Hz
Vrms = 12 V
F F www.schoolDD.com 20

22. XC XC = = =
XC = 96.5
Irms = =
Irms = 0.12 A Ans
.
L = 20 mH
f = 50 Hz
Vrms = 12 V
XL XL = L = 2 f L = 2x3.14x50x20x10-3
XL = 6.28
Irms = =
Irms = 1.91 A Ans
17.6 F F
PHILIPS
F
F HR 3312
BLADE SIZE 300 mm (12 )
VOLTAGE 220 V 50 Hz
POWER 45 W
AMPERE 0.25 A
F 0.83 m3/min/W
F F F F F F
F F F rms F (p ) F F
F F
p = IrmsVrmscos
F F F
cos F F F 1 ( = 0°)
F F www.schoolDD.com 21

23. - F i v = 0° --> cos = 1
F i v F 0° --> cos < 1
W t F
p =
W=p t
F
F F F F (W) F F F
F F F (UNIT )
1 F = 1 F
F F F F F ( ) F
F F F
-p F F p F F p
F F
F 11
F F F 485 F F 220 F
. F F F i
. F F F
. F F 0.5 v = 220 W
. F . F F F F F F 3 F F
Fp = 485 W , Vrms = 220 V , t = 0.5x60x60 = 1800 s cos = 1.0
. Irms = ?
p = IrmsVrmscos
Irms = = (cos = 1.0)
Irms = 2.2 A Ans
. R=?
R= =
R = 100 Ans
F F www.schoolDD.com 22

24. . W=?
p =
W = p t = 485x1800
W = 8.73x105 J Ans
. F
F . W = 8.73x105 J (= F )
F F F (=1 F )
W=
W = 0.24 F = 0.24 F
F F 3x0.24 = 0.72 Ans
F 12
i i = 5 sin ( t - 40°) F F v = 15 sin ( t +
20°)
.
. F F F
F i = 5 sin ( t - 40°) v = 15 sin ( t + 20°) FF v i F 20-(-40) = 60° Im =
5 A , Vm = 15 ( i = Im sin t v = Vm sin t)
. cos = ? , = 60°
cos = cos 60°
cos = ½ = 0.5 Ans
.p =?
p = IrmsVrms cos
= x x cos 60 = x x =
p = 18.75 W Ans
F 13
I1 , I2 I3 F F
I2 I1
120 V 40 W
800 W
40 W
I3 y x
F F www.schoolDD.com 23

25. F F F F F F F F
Vrms = 120 V
F F F F F p = IrmsVrms
Irms =
y= = A
x= = A
I1 = = A Ans
I2 = x + I1 = + = 7 A Ans
I3 = y + x + I1 = + + = 7.33 A Ans
17.7 F
N N
L L L
L
F 3 4
N L
F
F
L N
N
L
L
N
N L
F
F F
F F www.schoolDD.com 24

26. F F F F F F
F F F F F F 3
F F( L) ( N) F F L N F F
F F F F F
F
1. F F (cut-out) F F F F
F F F F F F F F
F F F F F F F F F F F F
F F F F
- F F F F
F F F F F F
F F F F F F F F F FF
F
2. F F F F F F
F F F F F
F F F
F F F F F
F 14
F F F F 220 F F F F F F F 600 F
750 F F 100 F F 150 F 40 F3 20 F5 F F
F
F F F
F F Vrms F F 220 V
Irms F F F p = Irms Vrms
Irms =
F F Irms1 =
Irms2 =
F Irms3 =
F Irms4 =
Irms5 =
F F www.schoolDD.com 25

27. Irms6 =
F Irms1 + Irms2 + Irms3 + Irms4 + Irms5 + Irms6 = = 8.27 A
p = 600 + 750 + 100 + 150 + (40x3) + (20x5)
= 1820 W
Vrms = 220 V
Irms = = 8.27 A
F 9A F 10 A F F F 10 A Ans
- F F F 1 Irms F F F F F F
F F F F F F F
F 15
F 100 F5 200 F 5 F F F F F
F 200 F F F F
F F Vrms F F 200 V
Irms F F F p = Irms Vrms
Irms =
Irms = = 0.5 A
Irms = = 1.0 A
F = 0.5x5 + 1.0x5 = 7.5 A
F F 8 A Ans
“
... ”
F F www.schoolDD.com 26