The details of this project are too long, so I am not going to bore you guys with them. What I am trying to do is to get the voltage across the right-hand side of the circuit to reach its highest and then drop abruptly to near zero. But what's happening is that it reaches its peak and then stays at that level (essentially, a voltage clamp). The Zeners are used to clamp the voltage at that level but I somehow need to drop it abruptly right after it peaks. Any suggestions?