what is transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power.It is composed of semiconductor material with at least three terminals for connection to an external circuit.he transistor provides current gain, allowing a relatively large current in the collector to be switched by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of transistor, and even for a particular type, varies depending on the collector current.