how much to bet in no-limit?

Lets say you raise preflop with AK in last position and get one caller. The flop hits your ace but there are draws on the board. You bet about the size of the pot and your opponent calls. Turn misses his draw and he checks. You are totally sure he is either on a draw or has a weak pair or weak kicker with his ace. You want to bet the turn so no free card is given... BUT the pot has gotten so large that in order to give him incorrect drawing odds you have to risk most of your stack. If you bet less then the pot you give him the chance to get good pot odds...

what do you do? how much do you bet to protect a made hand that is vulnerable to draws?

Depends on the draw you give him.
If he is on an open ended straigth then he has got 8 outs. If he is on a flush draw he has got 9 outs.
That leaves him with an 18-20% chance to hit his draw.
So if you bet 25% of the pot he makes a mistake if he calls this bet.
But it also depends on your opponent...
If he likes to call river bets you need to bet even more to keep him away from calling!

I think it also depends on the table limits. Smaller is less likely to consider pot odds, imo.

just bet enuff to give him an incorrect price to draw, regardless of how large a portion of ur stack it is

It depends on who you're up against.

Regardless of whether or not you price him out, he may have the outlook of "I've come this far, I might as well see the river"

If you think he is a good player that would consider pot odds, fire 1/2 the size of the pot at it.

This way, you will most likely get him off his hand if you have him beat like you think you do.

Just hope he doesn't have 2 pair or better!!!

Bigger turn bets tell you more about your opponents hand. If you bet small (25% pot) your opponent most likely will still call with his flush/straight draw, due to his/her implied odds. If you bet pot size you are going to see one of two things, fold or allin. The draw will fold and the set/two pair will push allin and you might be able to fold depending on your stack.

Like everyone else says, depends on who you're playing. One technique (which is generally not recommended but something to consider) is if you are sure he's going to call your bet regardless of the size of your bet, don't bet. You are last to act and get to see a free card. If you see he's missed his draw it has cost you nothing more. If you know he missed it, you fire away at him. Or if the pot is already large enough and you fear you've been betting into slow played two pr or trips then you can check and take it down. This is not my style of play but if you are worried about a short stack and you don't want to commit to a pot, sheepish is a technique. Short of that, I think a half pot raise should be enough to put a moderately skilled player off of a draw.

To tell you the truth, I'm not such a good player, but I think that it is not important how many chips to put in, you have to read the guy that you're playing against, and i'm talking about the style he plays. If he plays agressive and waiting for luck he will call you anyway for the draw and even raise you. If he plays tight he calls maybe because he got something.

if it's a tourney and you have to risk most of your stack to give him the wrong odds on the turn, then i would say just go ahead and push. but as with allmost all poker questions there are allways exceptions .gl