1. The problem statement, all variables and given/known data I need to find the output voltage mathematically or graphically 2. Relevant equations 3. The attempt at a solution My approach : as long as the Vi is < 9.3 V , the diode D1 will be ON because in that case VA will be < 10 V and current can flow through 10k resistor. And if this is true then D2 will also be 0N and Vo = Vi. Now second interval i.e Vi > 9.3 V, same reasoning for D3 i.e D3 will be ON as long as Vi > -9.3 V & D2 is ON & D4 is also ON. But in this case if we track from input to the output through D3 & D4 , then i get Vo = Vi and this is making D1 ON which i assumed to be OFF. Summarizing my results : 0<Vi<9.3 all diodes are ON & Vo = Vi Vi>9.3 all diodes are ON & Vo=Vi..... but this is not possible because this makes VA > 10 which shows current can't flow from +10V battery. So in short i know i am doing but the question is where ????