Example 1
You have
![The Ace of Clubs [Ac]](https://pofex.com/images/smilies/Ac.gif)
![The Two of Diamonds [2d]](https://pofex.com/images/smilies/2d.gif)
![The King of Diamonds [Kd]](https://pofex.com/images/smilies/Kd.gif)
![The Queen of Clubs [Qc]](https://pofex.com/images/smilies/Qc.gif)
![The Jack of Clubs [Jc]](https://pofex.com/images/smilies/Jc.gif)
![The Ten of Clubs [Tc]](https://pofex.com/images/smilies/Tc.gif)
![The Four of Diamonds [4d]](https://pofex.com/images/smilies/4d.gif)
Basically you are doing this to be able to control the pot and to react depending on what turns. The raise most likely means your opponent will check to you on the turn so if you brick everything your hand becomes much weaker so you can check and keep the pot small. However, if you hit something your hand will become dominant so you can bet again to increase the size of the pot.
Example 2
You have
![The Ace of Diamonds [Ad]](https://pofex.com/images/smilies/Ad.gif)
![The Jack of Diamonds [Jd]](https://pofex.com/images/smilies/Jd.gif)
![The King of Clubs [Kc]](https://pofex.com/images/smilies/Kc.gif)
![The Queen of Clubs [Qc]](https://pofex.com/images/smilies/Qc.gif)
![The Three of Diamonds [3d]](https://pofex.com/images/smilies/3d.gif)
![The Six of Diamonds [6d]](https://pofex.com/images/smilies/6d.gif)
![The Queen of Spades [Qs]](https://pofex.com/images/smilies/Qs.gif)
Here your draw is strong but your overall hand is weak. Most likely you barely have pot odds to call this bet, but if you keep the pot small you will have implied odds to call. Here you are controlling the pot by calling in order to not invest a lot of money with a mediocre hand and to increase your implied odds on later streets.
Example 3
You have
![The Ace of Diamonds [Ad]](https://pofex.com/images/smilies/Ad.gif)
![The Two of Diamonds [2d]](https://pofex.com/images/smilies/2d.gif)
![The King of Clubs [Kc]](https://pofex.com/images/smilies/Kc.gif)
![The Four of Clubs [4c]](https://pofex.com/images/smilies/4c.gif)
![The Jack of Clubs [Jc]](https://pofex.com/images/smilies/Jc.gif)
![The Nine of Spades [9s]](https://pofex.com/images/smilies/9s.gif)
![The Four of Diamonds [4d]](https://pofex.com/images/smilies/4d.gif)
![The King of Spades [Ks]](https://pofex.com/images/smilies/Ks.gif)
Your hand is pretty weak but nobody else has shown strength, so you bet 3/4 pot. This bet is both a steal attempt and controlling the pot. Most likely even if this bet get calls it will enable you to check behind on the river with your weak hand.
Hope this helps.