VLĐC02-8-vldcdaodongsonaaaaaaaaaaaaaaaaa

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1. Bμigi¶ngVËtlý®¹i c −¬ng
T¸cgi¶: PGS. TS §çNgäcUÊn
ViÖnVËtlýküthuËt
Tr−êng§H B¸chkhoaH μnéi

2. Dao ®éng& Sãng®iÖn
tõ
(Ch−¬ng8, 10)

3. 1. Dao ®éng®iÖntõ®iÒuhoμ:BiÕn®æituÇn
hoμngi÷ac¸c®¹i l −îng®iÖnvμtõ
K
2
+_
-+
D
max

M¹ch
kh«ng
cã
®iÖn
trë
thuÇn
, kh«ng
bÞ
mÊt
m
¸t
n¨ng
l
−
îng
Cq
21
W
20
max e
=
20
max m
LI
21
W
=
W
e
+W
m
=const
const
LI
21
Cq
21
2
2
=
+
0
dtdI
LI
dtdq
Cq
=
+
L
I
max
C
K
1

4. 0
dt
dI
L
C
q
=+
0I
dt
Id
2
0 2
2
=ω+
LC
1
2
0
=ω
LC2
2
T
0
0
π=
ω
π
=
Dao ®éng®iÖntõtrong
m¹ch LC l μdao®éng®iÒu
hoμ
tcosII
0 0
ω
=
I,q
t
tsinqq
00
ω
=
)tcos(II
0 0
ϕ
+
ω
=
LÊy®¹o h μmhaivÕ
theothêigian

5. 2.Dao ®éng®iÖntõt¾t dÇn
L
C
R
To¶
nhiÖt
t¹i R
Biªn
®é
dßng
(®iÖn
tÝch) gi¶m
dÇn
-
> t¾t h¼n
6.1
f/t
D
ao ®éng
®iÖn
tõ
t¾t dÇn
To¶
nhiÖt
t¹i R, mÊt
n
¨ng
l
−
îng
trong
d
t:
-dW= RI
2
dt
dt
RI
)
LI
21
Cq
21
(
d
2
2
2
=
+
−
2
RI
dtdI
LI
dtdq
Cq
−
=
+
RI
dtdI
L
Cq
−
=
+
0
I
dtdI
2
dt
I
d
20
2
2
=
ω
+
β
+ LR
2
=
β
LC1
0
=
ω

6. §iÒukiÖn®Ócãdao®éngω
0
> β
)tcos(eII
t
0
ϕ+ω =
β−
22
0
β−ω=ω
2
)
L2
R
(
LC
1
−=
I
t
I
0
e
-βt
-I
0
e
-βt
I
0
cosϕ
I
0
-I
0
T
2
)
L2
R
(
LC
1
2 2
T
−
π
=
ωπ
=
•I gi¶mdÇntheohμmmòvíi
thêigian
•§iÒukiÖn®Ócã
dao®éngω
0
> β
2
)
L2
R
(
LC
1
>
C
L
2R<
C
L
2R
0
=
•§iÖntrëtíih¹n

7. 3.Dao ®éng®iÖntõc−ìngbøc:
L
C
R
~
ε
dt.
I
.
dt
RI
)
LI
21
Cq
21
(
d
2
2
2
ε
=
+
+

Trong
t
hêi
gian
dt
mÊt
RI
2
dt
,
cung
cÊp
t
hªm
ε
Idt
ε
=
ε
0
sin
Ω
t t
sin
I
RI
dtdI
LI
dtdq
Cq
0
2
Ω
ε
=
+
+
t
cos
L
I
dtdI
2
dt
I
d
0
20
2
2
Ω
Ω
ε
=
ω
+
β
+
I=I
td
+I
cb
sau
m
ét
thêi
gian
I
td
t¾t h¼n, chØ
cßn
I
cb
I = I
cb
=I
0
cos(
Ω
t+
Φ
)

8. I
t
2 2
0
0
)
C
1
L(R
I
Ω
−Ω+
ε
=
R
C
1
L
tg
Ω
−Ω
=Φ
2 2
)
C
1
L(RZ
Ω
−Ω+=
Tængtrë
cñam¹ch
LZ
L
Ω
=
C
1
Z
C
Ω
=
C¶mkh¸ngDung kh¸ng
Céngh−ëngI
0
®¹t cùc®¹i
R
I
0
max0
ε
=
0 ch
LC
1
C
1
Lω==Ω→
Ω
=Ω
TÇnsèc−ìngbøc b»ngtÇnsèriªngcña
m¹ch -> Céngh−ëng

9. øngdông : HiÖusuÊtcaonhÊt-> Bïpha
Ω
I
0max
Ω
ch
=ω
0

10. Ch−¬ng10: Sãng®iÖntõ
1. Sùt¹o thμnhsãng®iÖntõ
ThÝnghiÖmcñaHÐc:
~
L
L’
A
B
Er
Hr
M
Sãng®iÖntõl μtr−êng®iÖntõbiÕnthiªn
truyÒn®i trongkh«nggian

11. 2. Ph −¬ngtr×nhM¾c xoencñasãng®iÖntõ
)t,z,y,x(EE
r
r
=
)t,z,y,x(DD
r
r
=
)t,z,y,x(HH
r
r
=
)t,z,y,x(BB
r
r
=
0
=
ρ
0J
=
r
t
B
Erot
∂
∂
−=
r
r
t
D
Hrot
∂
∂
=
r
r
0Ddiv
=
r
ED
0
r
r
εε=
0Bdiv =
r
HB
0
r
r
μμ=
Ph−¬ngtr×nhsãng
t
H
Erot
0
∂
∂
μμ−=
r
r
Erot
1
t
H
0
r
r
μμ
−=
∂
∂
t
E
Hrot
0
∂
∂
εε=
r
r
2
2
0
t
E
)
t
H
(rot
∂
∂
εε=
∂
∂
r
r

12. 2
2
0
0
t
E
)Erot(rot
1
∂
∂
εε=
μμ
−
r
r
0
t
E
)Erot(rot
2
2
00
=
∂
∂
εμεμ+
r
r
0
t
E
v
1
E
2
2
2
=
∂
∂
+Δ−
r
r
εμεμ
=
00
1
v
0
t
E
v
1
E
2
2
2
=
∂
∂
−Δ
r
r
με
=
C
v
s/m10.3
1
C
8
00
≈
εμ
=
EEEdiv)Erot(rot
2
r
r
r
r
Δ−=∇−∇=

13. 3. Nh÷ngt/ccñasãng®iÖntõ:
•Tånt¹i c¶trongchÊt, ch©nkh«ng
•Sãngngang: E&H vu«nggãcvíiv
•VËntèctrong
ch©nkh«ng
•VËntèctrong
m«itr−êngchÊt
με
=
C
v
s/m10.3
1
C
8
00
≈
εμ
=
Sãng®iÖntõ®¬n s¾c: MÆtsãngl μc¸cmÆt
ph¼ng song song: tõ∞,
ph−¬ngE,H kh«ng®æi
Er
Hr
vr
y
z
0
Er
0
Hr
x

14. Er
H
r
vr
HaivÐct¬lu«nvu«nggãc
HEr
r
⊥
v,H,E
r
r
r
theothøtù®ã hîpth μnhtam diÖn
thuËn3 mÆtvu«ng
H,Err
lu«ndao®éngcïngphavμcãtûlÖ
|H||E|
0 0
r
r
μμ=εε
)
v
x
t(cosEE
m
−ω=
)
v
x
t(cosHH
m
−ω=
4.N¨ngl−îngsãng®iÖn
tõ
2
0
2
0
H
2
1
E
2
1
μμ+εε=ϖ

15. Sãng®iÖntõlantruyÒn:

16. HEHE
0 0
2
0
2
0
μμεε=μμ=εε=ϖ
•N¨ngth«ngcñasãng®iÖntõ
v
ϖ
=Φ
εμεμ
=
00
1
v
EH=Φ
HEr
r
r
×
=
Φ
5. Thangsãngλ
cm
•VÐct¬Um«p-Poynting
10
-12
10
-10
10
-8
10
-6
10
-4
10
-2
10 10
2
SãngVT§
Hångngo¹i
AS nh×nthÊy
Tia r¬nghen
Tia Gamma
Tia töngo¹i

17. 6. ¸ p suÊtsãng®iÖntõ
Er
HrJr
Tr−êng®iÖntõg©yradßng
c¶møngJ -> g©yralùc®Èy
¸p suÊt p=(1+k) ϖ
ϖ≤p ≤2ϖ
AS mÆttrêicãn¨ngth«ngΦ~10
3
W/m
2
ϖ= Φ/c = 10
3
/(3. 10
8
)J/m
3
¸p suÊtAS mÆttrêit¸cdônglªnmÆtvËtdÉn
ph¶nx¹hoμntoμnk=1:
p=2. 10
3
/(3. 10
8
)=0,7.10
-5
N/m
2