电路理论/相量/范例/范例 7/mfile7a

format short
R = 10;
L = .01;
w = 377;
Vm = 120*2^.5;
omega = 2*pi/3;
Im = Vm/(R^2+(L*w)^2)^.5;
alpha = omega - atan(L*w/R);
syms t;
I = Im * cos(w*t+alpha);
Vr = R*I;
VL = L*diff(I,t);
fprintf('I is')
vpa(I,3)
fprintf('Vr is')
vpa(Vr,3)
fprintf('VL is')
vpa(VL,3)
fprintf('checking .. should equal 0')
subs(Vr,t,0) + subs(VL,t,0) - Vm*cos(omega)