Difference between Time-sharing computers and computers which use Round Robin scheduling algorithm?
No, they are not equivalent, but you are right to note a similarity.

Yes, a time sharing computer is one in which the computer switches between different processes.  The schedular is the part of the operating system that determines when to switch between processes, and which process to switch to.   A round robin scheduler is one particular type of scheduling strategy that could be used in a time sharing computer, but there are other possible scheduling strategies as well.