In most of the industrial processes it is required to rotate DC (or AC) motor forward and reverse for desired time. First motor rotates forward (clockwise) for some time (say 2 – 3 min) then it stops for some time. Again it rotates reverse (anticlockwise) for some time and rests. This process repeats every time when gets triggeredSequential timer is widely used circuit in industries because in most of the industries all the processes are of chain reaction type. That means one process ends and it triggers next. The last process triggers first process when it ends. And thus the cycle continues. These sequence timers are micro controller based multi-functional and programmable.But here we have a sequential timer using simple IC555. So let us see how it is done