clear; close all;clc
Imag=input('Enter the AC current peak amplitude (near 1 is best):');
Iphase=input('Enter the AC current initial phase (radians) (better to avoid 0 here):');
Ifreq=input('Enter the AC current frequency (randians/sec):');
disp('Now select the device impedance with left mouse');
disp('Use right mouse over complex plane to exit');

I=Imag*exp(i*Iphase);

run=1;
while run==1

    theta = 0:pi/50:2*pi;
    uncirc = exp(i.*theta);
    figure(1) 
    hold on;
    nl=-1.4:.2:1.4;
    plot(nl + i*.0001,'g'),
    plot(.0001+ i.*nl,'g'),
    for n=-1.4:.2:1.4,
        plot(nl + i*(n+.0001),'b'),
        plot(n + i.*nl,'b'),
    end
    plot(uncirc,'g')
    plot(nl + i*.0001, 'g'),
    plot(.0001+ i*nl, 'g'),
    axis('square');
    axis([-1.5,1.5,-1.5,1.5]);
    xlabel('Real');
    ylabel('Imaginary');

    [X,Y,BUTTON] = ginput(1); 
    Z=X+i*Y;
    clf;
    if BUTTON==3
        close all
        break
    end

    plot(X,Y,'rx');
    r=abs(Z);
    thetaZ=angle(Z);
    hold off

  
    
    S2=sprintf('V=IZ=%.2f e^{j(%.2f)} %.2f e^{j(%.2f)}',Imag,Iphase,r,thetaZ);
    h2=text(-1.4,1.25,S2); 
    set(h2,'FontSize',16);
    S2=sprintf('V=%.2f e^{j(%.2f)}',Imag*r,Iphase+thetaZ);
    h2=text(-1.4,.75,S2); 
    set(h2,'FontSize',16);

    figure(2)
    t=linspace(0,6*pi/Ifreq,1000);
    current=Imag*cos(Ifreq*t+Iphase);
    Vmag=Imag*r;
    Vphase=Iphase+thetaZ;
    V=Vmag*exp(i*Vphase);
    x=Vmag*cos(Ifreq*t+Vphase);
    plot(t,current,'b-',t,x,'g-');
    legend('Current i(t)','Voltage v(t)');
    grid
    xlabel('t');
    ylabel('v(t) (Volts), i(t) (Amps)');
    axis tight;
 

    S=sprintf('v(t)=%.2f cos(%2.f t + (%.2f))',Vmag,Ifreq,Vphase);
    h=text(pi/(2*Ifreq),-.8*Imag,S); 
    set(h,'FontSize',18);
    S=sprintf('i(t)=%.2f cos(%2.f t + (%.2f))',Imag,Ifreq,Iphase);
    h=text(pi/(2*Ifreq),.8*Imag,S); 
    set(h,'FontSize',18);
 

    figure(3)
    plot(real(I),imag(I),'b*',X,Y,'r*',real(V),imag(V),'g*');
    legend('I','Z','V');
    
    hold on
    r1=linspace(0,Imag,100);
    r2=linspace(0,r,100);
    r3=linspace(0,Vmag,100); 
    
    plot(r1*exp(i*Iphase),'b-')
    plot(r2*exp(i*thetaZ),'r-')
    plot(r3*exp(i*Vphase),'g-')

    axis equal   
    ylabel('Imaginary Axis');
    xlabel('Real Axis');
    title('V=IZ');
    hold off
    
end