Its a triggering circuit that i want to build for firing the SCR's(used in the Rectifier Bridge). Problem is the the pulse to be fed to the SCR's has to be in synchronization with the A.C source to be fed to the SCR's. So Synchronizing this pulse would require first converting into A.C into Square Wave pulse...Friends recommmended to use lm324 as comparator for the circuit...Can anyone guide me on this first step?