the capacitor_value is returning Nan

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Badr Al-Sabri
Badr Al-Sabri 2022-5-7
评论： Voss 2022-5-7
% --- Executes on button press in calculate_button.
function calculate_button_Callback(hObject, eventdata, handles)
option = get(handles.resistance_value, 'value');
switch option
case 1
R = 1000;
case 2
R = 2000;
case 3
R = 3000;
case 4
R = 4000;
end
R = str2double(R);
f_c = get(handles.f_value,'string');
f_c = str2double(f_c);
c_value = 1 / (2*pi*R*f_c);
c_value = num2str(c_value);
set(handles.capacitor_value,'string',c_value);

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Voss
Voss 2022-5-7
Ran in:
In the switch block, R is set to a double already, so it is not correct to do str2double after that. In fact, doing so makes R into NaN:
% option = get(handles.resistance_value, 'value');
option = 1; % hard-coded for demonstration
switch option
case 1
R = 1000;
case 2
R = 2000;
case 3
R = 3000;
case 4
R = 4000;
end
R = str2double(R)
R = NaN
So then C calculated from R=NaN is NaN as well:
% f_c = get(handles.f_value,'string');
f_c = '33'; % hard-coded for demonstration
f_c = str2double(f_c);
c_value = 1 / (2*pi*R*f_c)
c_value = NaN
c_value = num2str(c_value)
c_value = 'NaN'
Simply remove the erroneous R = str2double(R); line:
% option = get(handles.resistance_value, 'value');
option = 1; % hard-coded for demonstration
switch option
case 1
R = 1000;
case 2
R = 2000;
case 3
R = 3000;
case 4
R = 4000;
end
% R = str2double(R);
% f_c = get(handles.f_value,'string');
f_c = '33'; % hard-coded for demonstration
f_c = str2double(f_c);
c_value = 1 / (2*pi*R*f_c)
c_value = 4.8229e-06
c_value = num2str(c_value)
c_value = '4.8229e-06'
  2 个评论
Voss
Voss 2022-5-7
You're welcome! If that solves the problem, please click "Accept This Answer". Thanks!

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