I think the power attack is just as silent as a normal swing, the grunt/yell is purely for effect.  I went up behind an enemy and whiffed a bunch of power attacks on purpose and he had no reaction whatsoever, then I finished him off with a power attack and a nearby patrolling enemy didn't react.

I have to add an addendum to this:

Power attacks can sometimes push your character forward a little bit on the swing, and this can cause you to be detected before the attack connects, making you lose the sneak attack bonus.  Make sure you are standing far back enough for this to not happen.

Does using a Power-attack while sneaking increase your chances of being detected?
Design giving the necessary ratings and characteristics the necessary for the transformer, bridge rectifier capacitor and regulator , a 12v , 2A regulated power supply .

the available mains supply is 230v+10% @50hz

so far I have : 

Regulator - Standard voltage regulator will require 2v to be maintained across it to prevent drop out , therefore input voltage should not drop below 14v 

Transformer - Va atleast  50% &amp; volt drop = 24v 

Capacitor - the minimum peak voltage to the regulator input 

(24-10%) x 1.414 - 2 = 28.8v

maximum peak voltage 

(24+10%+10%)x1.414-1.4 = 38.9v 

The minimum peak full hand voltage defines the minimum of ripple voltage 
(28.8-14) = 14.8

suitable reservoir capacitor ? 

I am uncertain if these figures are even correct , I think I am close but could do with some guidance 

thank you
