Abstract
The theory of weak localization is discussed for the case of a normal-metal loop with symmetric side arms for boundary conditions under realistic experimental situations. The magnitude of h/2e oscillations in magnetoresistance is quite sensitive to the experimental geometry, as was pointed out by Douçot and Rammal. In the case of a short wire, with a loop outside the voltage and current leads at one end, a changing magnetic field modifies the boundary condition at the end of the wire periodically to give h/2e oscillations in the magnetoresistance of the wire.