Pogo pin

A pogo pin or spring-loaded pin is a type of electrical connector mechanism that is used in many modern electronic applications and in the electronics testing industry. They are used for their improved durability over other electrical contacts, and the resilience of their electrical connection to mechanical shock and vibration. A pogo pin or spring-loaded pin is a type of electrical connector mechanism that is used in many modern electronic applications and in the electronics testing industry. They are used for their improved durability over other electrical contacts, and the resilience of their electrical connection to mechanical shock and vibration. The name pogo pin comes from the pin's resemblance to a pogo stick – the integrated helical spring in the pin applies a constant normal force against the back of the mating receptacle or contact plate, counteracting any unwanted movement which might otherwise cause an intermittent connection. This helical spring makes pogo pins unique, since most other types of pin mechanisms use a cantilever spring or expansion sleeve. Spring-loaded pins are manufactured with a turning process which does not require a mold, thus allowing the production of smaller quantities at a lower cost. A basic spring-loaded pin consists of 3 main parts: a plunger, barrel, and spring. When force is applied to the pin, the spring is compressed and the plunger moves inside the barrel. The shape of the barrel retains the plunger, stopping the spring from pushing it out when the pin is not locked in place. In the design of electrical contacts, a certain amount of friction is required to hold a connector in place and retain the contact finish. However, high friction is undesirable because it increases stress and wear on the contact springs and housings. Thus, a precise normal force, typically around 1 newton, is required to generate this friction. Since a spring-loaded pin needs to have a slight gap between the plunger and barrel so that it can slide easily, momentary disconnections can happen when there is vibration or movement. In order to counter this, the plunger usually has a small tilt to ensure a continuous connection. Many manufacturers have created their own proprietary variations on this design, most commonly by varying the interface between the plunger and spring. For example, a ball may be added between the two components, or the plunger may have an angled or countersunk tip. The plunger and barrel of pogo pins usually use brass or copper as a base material on which a thin layer of nickel is applied. As common in electrical connectors, manufacturers often apply a gold plating that improves the durability and contact resistance. The springs are usually made of copper alloys or spring steel.