Yeah maybe around that, except everything goes WHITE and blurry for a while.
And when you regain sight you be dead.

Stun grenades have got to be one of the most annoying little #!&$ers I've ever played against. Every time someone else uses them, I find myself staring at them - every time I throw them, nobody seems to be looking until after.
That said, Support has plenty of kewl stuff already. You want to disable people in an area, throw a smoke grenade on top of them. It will force them to either a) stop shooting or b) run out of cover, which is the whole idea. If you're Support, then have a Trooper chuck the smoke while you resupply them.

That's actually a side-effect of grenades exploding. You'll notice it if something explodes near you in Vanilla - you'll get a ringing sound in your ears, a byproduct of being deafened, as well as a visual effect that I liken to a concussion. A great way to experience it, by the way, is to play PR (admitedly, BF2, but the effect is the same), grab the Civilian kit, and throw a rock while facing straight down. The rocks actually 'explode' and cause the deafening effect after a second!