Hi
I am using push button. I am reading HIGH from the switches. My model doesn't allow to use push button. What can replace those push buttons?
My project is about servo motors which rotate when the switches are HIGH or various combinations of switches. some sliding movement is happening.
Could anybody suggest what will be the best?
Thank you 
As I read in the articles, can I use transistors for external switching operations?
You questions are a little confusing. What is it you are trying to do?
I agree with James...
With no reference to what you mean by "My model doesn't allow to use push button.", we have very little to work with to give you answers.
So, are transistors just like a switch? No.
Can they be used emulate a switch closure? Maybe... but limitations and conditions created by the "unknown" circuit prevent us from providing any sort of answer that contains a "design" you can use.
Cross-posted:
Cross-posting wastes time. DON'T DO IT.