function Ne = SC_potential( db, t_start, Dt, SC )

  disp('Reading SC potential data.');

  SC_str = int2str( SC );

  [t_E1, E1] = isGetDataLite( db, t_start, Dt, ...
               'Cluster', SC_str, 'efw', 'E', 'p1', '10Hz', 'lx');
  [t_E2, E2] = isGetDataLite( db, t_start, Dt, ...
               'Cluster', SC_str, 'efw', 'E', 'p2', '10Hz', 'lx');
  [t_E3, E3] = isGetDataLite( db, t_start, Dt, ...
               'Cluster', SC_str, 'efw', 'E', 'p3', '10Hz', 'lx');
  [t_E4, E4] = isGetDataLite( db, t_start, Dt, ...
               'Cluster', SC_str, 'efw', 'E', 'p4', '10Hz', 'lx');

  E1 = real(double(E1));
  E2 = real(double(E2));
  E3 = real(double(E3));
  E4 = real(double(E4));

  % Resample (using lookup) with E1 as reference (if existing).
  E2 = interp1( t_E2, E2, t_E1 );
  E3 = interp1( t_E3, E3, t_E1 );
  E4 = interp1( t_E4, E4, t_E1 );

  E_tot = (E1 + E2 + E3 + E4) ./ 4;

  % Infer the plasma density from these spacecraft potentials.
  % Based on Arne Pedersens "hand-plot" vs WHISPER calibration.
  % (VERY preliminary).
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  E_abs = abs(E_tot);

  % Results in cm(-3).
  %%%%%%%%%%%%%%%%%%%%
  Ne_tmp = Upot2Ne(E_abs);

  % Make time first element in vector.
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  Ne    = [t_E1 Ne_tmp E_tot];

  return;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

