A balun, ("bal-un"),'s a type of electrical transformer that can convert electrical signals that're balanced about ground (differential) to signals that're unbalanced (single-ended) and vice versa. They're also often used to change impedance. Baluns can take many forms and their presence isn't always obvious. They always use electromagnetic coupling for their operation. Types of balun Autotransformer type In an autotransformer, two coils on a ferrite rod can be used as a balun by winding t… (More on Balun)