regarding the error in matlab

HI all i was trying to calculate the transfer function of an regulator i wrote below kcl nodal equations

clc;
clear;
%for test transfer function
syms s x y z G_MOTA R_OTA C_OTA s g_mbuf C_gdMN ...
    C_gsMN g_mMN R_L C_L R_1 R_2 C_1 C_2 V_out V_in

S1= solve( 's*C_1*(V_in-x)+(V_in-x)/R_1=x/R_2+s*C_2*(x-z)',V_in,...
    '-G_MOTA*x=y/R_OTA+s*C_OTA*y ' ,y ,...
    'y*g_mbuf=g_mbuf*z+s*C_2*(z-x)+s*C_gdMN*z+s*C_gsMN*(z-V_out)' ,z ,...
    '(g_mMN+s*C_gsMN)*(z-V_out)=s*C_L*V_out+V_out/R_L',V_out);

TF = (S1.V_out/S1.V_in);

H=collect(TF,s)

i am getting this below error

Struct contents reference from a non-struct array object.

Error in sym/subsref (line 881)
            R_tilde = builtin('subsref',L_tilde,Idx);

Error in tranfun (line 12)
TF = (S1.V_out/S1.V_in);

Answer 1

[manish srivastava]

It is working now thanks you very much

[Stephan]

Glad to hear - you can accept and/or vote for helpful answers in order to help people with similar problems finding useful answers. Also this is the way how the volunteers here warm reputation.

Answer 2

[Stephan]

Hi,

try:

syms s x y z G_MOTA R_OTA C_OTA s g_mbuf C_gdMN ... 
    C_gsMN g_mMN R_L C_L R_1 R_2 C_1 C_2 V_out V_in
eqn = [s*C_1*(V_in-x)+(V_in-x)/R_1 == x/R_2+s*C_2*(x-z),...
    -G_MOTA*x == y/R_OTA+s*C_OTA*y,...
    y*g_mbuf == g_mbuf*z+s*C_2*(z-x)+s*C_gdMN*z+s*C_gsMN*(z-V_out),...
    (g_mMN+s*C_gsMN)*(z-V_out) == s*C_L*V_out+V_out/R_L];
vars = [V_in, y, z, V_out];
S1 = solve(eqn, vars);
TF = (S1.V_out/S1.V_in);
H=collect(TF,s);

[Torsten]

manish srivastava's answer moved to a comment

error gone thanks you but nothing is comming out as outputt