  We investigate the possibilities of a tight binding ladder network as a
mesoscopic switching device. Several cases have been discussed in which any one
or both the arms of the ladder can assume random, ordered or quasiperiodic
distribution of atomic potentials. We show that, for a special choice of the
Hamiltonian parameters it is possible to prove exactly the existence of
mobility edges in such a system, which plays a central role in the switching
action. We also present numerical results for the two-terminal conductance of a
general model of a quasiperiodically grown ladder which support the general
features of the electron states in such a network. The analysis might be
helpful in fabricating mesoscopic or DNA switching devices.
