// event models gate opening/closing
math main {
  realDomain t;
  t.min=0; t.max=10; t.delta=0.1;
  extern real V(t);
  real V1 = 10;
  real V0 = 5;
  intState open(t);
  when (t=t.min) open = 0;
  event (open=0 and V>V1) open = 1;
  event (open>0 and V<V0) open = 0;
}