When put the DB() function the x-axis become log-scale is it? And for the red circled region is it caused by the delay of capacitor? Wondering why the voltage raise in the red-circled region... And for the voltage gain for 2nd order low pass, why after certain frequency the gain raise again for the below graph(Left)? Why the graph is different if we not using DB() function? upper is using DB() lower is without using DB(). Thanks, if anyone could to explain to me...thz vry much.