A Fuzz Button is a high performance 'signal contact' typically fashioned from a single strand of gold-plated beryllium copper wire formed into a specific diameter of dense cylindrical material, ranging from a few tenths of a millimetre to a millimetre. They are often used in semiconductor test sockets and PCB (board-to-board) interconnects where low-distortion transmission lines are a necessity. The term "Fuzz Button" was originally conceived and trademarked by Tecknit, but is now owned by a Denver-based company called Custom Interconnects.
They can be used discretely as a signal/ground contact or for Electromagnetic interference (EMI) protection. When a specific mating array is needed, Fuzz Buttons can be placed in thru-holes in an insulated piece of material, such as dielectric plastic.
Practical uses
Fuzz Buttons are commonly utilized in satellite and space applications, but are also broadly used in military and commercial applications.