文档介绍：Basic Circuit Theory
Chpter7 Problems
1 A cosine voltage is zero and increasing at t = - ; the next zero crossing occurs at t =
. (a) Calculate T, f, and ω. (b) If v(0) = 20V, find v(t). (c) By what angle does v(t)
lead the current i(t) = 5cos(ω t - 110 o ) A?
2 For the sinusoidal waveform shown in -11, (a) find T, f, ω, ϕ, and A if f(t) = A sin(ω t
+ ϕ); (b) find θ, A, and f() if f(t) = 5cos(ω t + θ).
f (t)
8
t(ms)
0
− 5
− 8
Fig. 7-11 For .
3 With reference to the circuit of -12 let i = 2sin(500t - 40 o ) A, R = 200 Ω, and L = .
Determine the source voltage v S (t).
-
+ v R
R
+
v s
- L
i
Fig. 7-12 For .
4 A inductor having a wire resistance of 10 Ω is connected to a 50 Hz source. If the
open-circuit source-voltage amplitude is 120 2 V and its internal resistance is 2 Ω, find the
amplitude of the sinusoidal voltage across the inductor ( and 10 bination).
o (− )
5 Give in polar form for: (a) 20 ∠ 110 o - 8 ∠ 40 , (b) . Give in rectangular
( + )
j o
form for: (c) , (d) e ∠52 .
−
o
6 (a) plex current, 8e j(200t−60 ) A, is applied to the bination of a 12 Ω
resistor and a 20mH inductor. Assuming the passive sign convention, find plex
o
voltage across bination. (b) plex voltage, 60e j(10000t+150 )