A minimum number of links that can make a mechanism are:

Explanation:

• A kinematic chain is a group of links either joined together or arranged in a manner that permits them to move relative to one another. 

Now, let's take an example of such a mechanism

The above-shown figure is a cam and follower mechanism. 

In this mechanism, there are 2 lower pairs i.e. between links (1,2 and 3,1) and 1 higher pair which is between link (2,3). 

Hence, the minimum number of links that can make a mechanism is 3.

Mistake Points

If it is given in the question that all the pairs are lower pairs then the correct answer will be 4.

If the links are connected in such a way that no motion is possible, it results in a locked chain or structure.

A minimum number of three links is required to form a closed chain but there will be no relative motion between these three links if all are lower pairs. Hence it cannot form a kinematic chain.

So the minimum of four links is necessary to form a kinematic chain when all the lower pairs are used.