Technician increases the power of moves - that are usually base power 60 or below - by 50%.
Moves with variable base power are boosted only when it is 60 or below. For example, if Magnitude hits at level 6 it will be boosted from 50 to 75, but level 7 will stay at 70 base power.
Moves like SonicBoom that deal fixed HP damage are not affected by Technician.