Jumpers: Characteristics and Functions

In computing, a jumper is a pair of prongs used as electrical contact points installed within a computer motherboard or an adapter card. Jumpers are used to open, close, or bypass part of an electrical circuit, and are commonly employed as an alternative to a DIP switch. This blog will explain jumpers, their characteristics, and uses.

Jumper prongs are arranged in groups called jumper blocks, with each jumper block having one or more pairs of contact points. A conductive sleeve (this sleeve is the jumper itself) is placed over the prongs, completing the electrical circuit. Functioning jumpers must be electrically conductive, though they are usually encased in a non-conductive block of plastic for convenience. This plastic enclosure also helps mitigate the risk that an unprotected jumper will cause a critical circuit to short. Jumpers could also be thought of as on/off switches, as they can be removed or added to enable further performance capabilities of a given component. When a jumper is ‘on’ it is covering two prongs and is considered a closed jumper. When a jumper is off, it is covering only one prong and is considered an open jumper.

Jumpers were predominantly used within older PC systems, where setting jumpers often maintained the speed and voltage settings of the central processing unit. Additionally, jumpers and jumper blocks were used to reset the basic input/output system configuration and clear complementary metal oxide semiconductor information. Older PCs contained one or more jumpers and a bank of DIP switches. It was not uncommon for motherboards to consist of up to 40 jumpers. In more modern computing technology, jumpers are rarely seen on motherboards. Instead, speed and voltage settings are configured automatically or through a software program.

This does not mean that jumpers are now obsolete, as they are still very commonly found on modern hard drives. A chief advantage of jumper’s is their one-time configuration, which makes them less vulnerable to corruption or power failure than firmware. Additionally, jumpers are fast and easy to set up even without technical expertise. In PCs, jumpers were largely replaced by plug and play (PnP) technology. PnP refers to a configuration in which a device features a specification that facilitates the discovery of a hardware component in a system without the need for physical device configuration or user intervention in resolving resource conflicts.

In certain printed wiring assemblies, especially those that utilize single-layer circuit boards, there are short lengths of wire soldered between pairs of points. These wires are called jumpers, but unlike typical jumpers, these are intended to permanently connect the points. This type of jumper is used to solve wiring layout issues and provide connections that would otherwise require complicated routing of the wires. Jumpers are a critical tool in any electronic system, so it's important that yours come from a trusted supplier. For all your jumper needs and much more, look no further than ASAP Semiconductor.

At ASAP Semiconductor, a division of AFR Enterprises, we can help you source all types of jumpers, electronic circuits, and general electronic equipment and deliver them with some of the industry’s best lead times. Additionally, as ASAP Semiconductor is the only independent distributor with a strict No China Sourcing Policy, we can guarantee that each part you buy from us will come from a trusted electronics manufacturer. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@asapsemi.com or call us at 1-714-705-4780. Our team of dedicated account managers is standing by and will respond to you in 15 minutes or less.