. 1 , C, L R.
- (. . .) , , .
, R = 0 q 0.
C :
W C = q 02/2 C = CU 02/2,
U 0 = q 0/ - . . :
I (t) = dq (t)/ dt, (1)
dq (t) . , (dq < 0).
, , . (dI > 0) L (. . .) E (t), (E < 0):
E (t) = L (dI/dt).
, , , I 0. :
W L = LI 02/2.
. . . . , . . . , . , , , . . . .
T.
, .
R, W :
Q = W R = I 2 Rt.
. .
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U (t) = j1 - j2 . , , ... :
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, (1) q = CU. (2) :
LC (d 2 U/dt 2) + RC (dU/dt) + U =0 (3)
(3) LC
R/ 2 L = β, 1/ LC = w02,
w0 () , b , :
d 2 U/dt 2 + 2b(dU/dt) + w02 U = 0, (4)
U (t).
, , , , ( , ) .
, , , , , . (4) . , b < w0, :
U (t) = U 0 e- b tcos (w t + j0), (5)
j0 ; w :
w = = (6)
. 2 U (t) .
(5) (. 2)
T = = . (7)
A (t) = U 0 e- b t, (8)
U 0 :
U 0= A (t = 0).
, b¹ 0 U (t) : U (t) ¹ U (t + T). .
(5) (8), b. (8) , t, :
U 0/ A (t) = e t = t= 1/b.
, R, L C. , b = 0 ( ) (. 2):
U (t) = U 0 cos (w0 t + j0)
T 0 = 2p / w0 = 2p ( .).
(. (6) (7))
R = R = 2
b = w0 . , , (. 2).
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R < R (. . b < w0) (. 2).
R > R (b > w0) w . (. 2).
b : d Q.
, (. 2):
d = ln = ln = b T = T /t = 1/ N, (9)
.. , (), (N = t/ T).
Q , , . , , :
Q = w0/2b.
b ω w0 (. (6)) , (9), :
Q = w0/2b ≈ w/2b = 2p/2β T = p/d.
:
b = R /2 L, w0 = 1/ .
:
Q = w0/2b = = r /R. (10)
r = .
(10) , , , , .
R, L C. , , , . . R, L , , . .