clear; close all
%
%  Sample problem 6-12, cleaned up
%
V0 = 12;    %% volts
C = 45;     %% mu-farads
%C = 10;
C = C/1.e6; %% farads
R = 1.8;    %% k-ohms
R = R*1000; %% ohms
f = 60;     %% freq, Hz
Tf = 70;    %% msec
Tf = Tf/1000;
omega = 2*pi*f; %% radian freq
tc = R*C;       %% time constant
dt = 0.05e-3;
t = 0:dt:Tf;
state = 'on';
loss = 0;
for i=1:length(t)
    Vs(i) = V0*sin(omega*t(i));
    switch state
        case 'on'
            VR(i) = Vs(i);
            iR = Vs(i)/R;       %% current thru R
            iC = omega*C*V0*cos(omega*t(i));    %% current thru C
            if iR+iC <= 0        %% check for current reversal
                state = 'off';
                tA = t(i);      %% keep track of reversal time
            end
        case 'off'
            tt = t(i)-tA;
            VR(i) = V0*sin(omega*tA)*exp(-tt/tc);
            if Vs(i) >= VR(i)   %% check for reversal
                state = 'on';
            end
    end
    loss = loss + R*iR^2;
end
plot(t,Vs,'r',t,VR,'k')
xlabel('Time, sec');
ylabel('Voltage');
title(sprintf('Rectifer response for C = %d mu-F',C*1e6))
text(Tf/2,0,sprintf('%5.2f m-watts loss',loss*1000));
grid