HH
2.1. pp p
p p p p p. p pp , , :
I = dq / dt (2.1)
p - p (A).
p pp p j, p p, p p p (. 2.1):
j = (dI/dS) n, (2.2)
n - , .
- j
dS v - n
E
L
.2.1
p j p p , p p , p (p. 1.3).
j. L V = LdS = <v>tdS (.2.1), <v>- , dS - , , t = 1. V n, N = nV. qnV, q - . ,
j = n<v>q. (2.3)
j , . (2.1)
I = q / t (2.4)
/ 2.
p p
p p p
R = r l /s, (2.5)
l - p; s - p ; r - p p. p (), . .
, p p, p p p:
g = 1/ r. (2.6)
, p , (); p (/).
p p . Hpp, p pp r p p pp:
r = r0 (1 + a t), (2.7)
r - p p pp t;
r0 - p p pp 0; a - pp p. a = 0.004 K -1. , R , (2.7).
:
n
R = R1 + R2 + R 3 +....+ Rn, = Σ Ri (2.8)
i = 1
|
|
:
n
1/ R = 1/ R1 + 1/ R2 + 1/ R3 +... + 1/ Rn = Σ(1/ Ri). (2.9)
i = 1
, , , . , , , . pp p p p () - , p p p p p p p p. , (. 2.2,), - (. 2.2,).
φ1 φ2 φ1 e12 r φ2 e12 r
R R
1 2 1 - + 2
R
. 2.2
p ( ) 1-2 (. 2.2)
U12 = φ1-φ2 e12, (2.10)
φ1-φ2 - ; e12 - , . p p (, p p p p , , p ), p "", p - co "".
p U12 p p, p 1 2. p U12 - p , p φ1-φ2. p p p . ().
:
I = (φ1-φ2)/R12 = U12/R12, (2.11)
:
I = (φ1-φ2 e12)/ R12 = U12)/ R12, (2.12)
R12 - 1 - 2.
(. 2.2,) 1 2 , .. j1 = j2. p (2.12) pp :
I = e /(R+ r), (2.13)
e r - () , ; R - .
.
p d l, ds p
dU = Ed l, (2.14)
- p p . :
dI = dU/R = Ed l /(rd l /ds)= E ds /r = gEds. (2.15)
j = g E. (2.16)
p p:
j = g E. (2.17)
p p- . , p (2.17) p :
j = g(E + E *), (2.18)
E * - p p p . p (2.18) p p.
. q, R = 5 U1= 2 U2 = 5 t = 10 .
|
|
. , (2.1):
t
dq = I dt, q = òI dt.
0
(2.11),
t
q = ò(U /R)dt.
0
U , :
U = U1+ kt,
k - , , .
5 = 2 + k10; k = (5 2)/10 = 0,3(/); U = 2 + 0,3t.
10 10 10
q = ò(2 + 0,3t /R)dt = ò(2/R) dt + ò(0,3t /R)dt =
0 0 0
10
= (2t/R + 0,3t2 /2R)| = 210/5 +0,3102 /10) = 7().
-. .
. . .
, p p p p dq dt, p
d = I U dt = I2R dt = (U2/ R) dt (2.19)
p p , p p I
= I U t = I2R t = (U2/ R) t (2.20)
- p, p p: R
= d/dt = I U = I2 R = U2/ R. (2.21)
0 = I ε = I2 R = I2(R + r) = I2R + I2r. (2.22)
0 = I ε , p , I2R, R - (), I2r - p (Δ) p p r. - (), - ().
() η , .e.
η= n / 0 = U/ε (2.23)