TWO MODELS:

--We have performed a series. of experiments to investi gate two "models" for studying the behavior of weak-link Josephson effect structures. The fi.rs.t is a low-induc tance, externally shunted, oxide-barrier Josephson junc tion. This acts as a generalized weak link in that it can be adjusted, even at liquid helium temperatures, to replicate the I-V characteristics of widely varying types of weak links. The other model is a driven, damped pen dulum whose equation of motion is equivalent to the second-order nonlinear current-phase equation of the links. Observations on both models not only indicate the correctness of the assumed equivalent circuit by verifying the solutions in detail, they provide new physical inSight into the nonlinear behavior of the phase and thus of the current-voltage relationship of weak links in general.