A controller will be designed using a sufficient number of OPAMPs and level sensors for a fuel tank filling system. The filling process will be stopped when the controller output is $0.$ The level sensor$,$ which is active when the tank is completely full, produces $12$V voltage. The maximum level value to be taken as a reference is $5$ volts. We tried to design a circuit suitable for this. but this circuit does not work.Where did we go wrong?