  We explore OR gate response in a mesoscopic ring threaded by a magnetic flux
$\phi$. The ring is symmetrically attached to two semi-infinite one-dimensional
metallic electrodes and two gate voltages, viz, $V_a$ and $V_b$, are applied in
one arm of the ring which are treated as the two inputs of the OR gate. All the
calculations are based on the tight-binding model and the Green's function
method, which numerically compute the conductance-energy and current-voltage
characteristics as functions of the gate voltages, ring-to-electrodes coupling
strengths and magnetic flux. Our theoretical study shows that, for
$\phi=\phi_0/2$ ($\phi_0=ch/e$, the elementary flux-quantum) a high output
current (1) (in the logical sense) appears if one or both the inputs to the
gate are high (1), while if neither input is high (1), a low output current (0)
appears. It clearly demonstrates the OR gate behavior and this aspect may be
utilized in designing the electronic logic gate.
