  The non-linear current-voltage characteristic of a tunnel junction between
two Luttinger systems is calculated for an interaction with finite range.
Coulomb blockade features are found. The dissipative resistance, the
capacitance and the external impedance, which were introduced ad hoc in earlier
theories, are obtained in terms of the electron-electron interaction. The
frequency dependence of the impedance is given by the excitation spectrum of
the electrons.
