  We study the nonlinear behaviors of mass-spring systems damped by dry
friction using simulation by a nonlinear LC circuit damped by anti-parallel
diodes. We show that the differential equation for the electric oscillator is
equivalent to the mechanical one's when a piecewise linear model is used to
simplify the diodes I-V curve. We derive series solutions to the differential
equation under weak nonlinear approximation which can describe the resonant
response as well as amplitudes of superharmonic components. Experimental
results are consistent with series solutions. We also present the phenomenon of
hysteresis. Theoretical analysis along with numerical simulations are conducted
to explore the stick-slip boundary.
  The correspondence between the mechanical and electric oscillators makes it
easy to demonstrate the behaviors of this nonlinear oscillator on a digital
oscilloscope. It can be used to extend the linear RLC experiment at the
undergraduate level.
