This information is part of the Modelica Standard Library maintained by the Modelica Association.
This example is a simple circuit for overvoltage protection. If the voltage zDiode_1.n.v is too high, the Diode zDiode_2 breaks through and the voltage gets down.
The simulation end time should be set to 0.4. To get the typical behaviour please plot sineVoltage.p.v, RL.p.v, zDiode_2.n.v and zDiode_1.n.i.