A transistor can automate things like blinking toys by turning on and off really fast. Collector collects electricity. It is the part of the path which amplifies signal. Emitter emits the electricity. It works with base to control the flow of electricity. Base- when you give a tiny electric signal, it opens the door for bigger electricity to pass from collector to emitter. Together they make things turn on and off and amplifies signal. Silicon is the most common semiconductor.