How to create a flickering light source using cycles? I tried doing this using the 'Noise' option in the F-Curve Modifier, but i did not see and significant flickering. Am I doing something wrong? Or is there any other way this output can be achieved. 
Also, is there any way to rapidly and randomly change the shape of a object --like a sphere or icosphere -- to further assist the flickering effect?
Try increasing the strength value.