An antistatic wrist strap is a bracelet-like strap that a wearer uses to dissipate the static charge that may short out computer components. The strap is made of a static discharging material with a resistor that has one metal side and a cord receptacle on the other side. The metal side of the resistor must be in contact with a user's bare skin, or static charge will not be dissipated. The other component of a wrist strap is the cord, which needs to complete the discharge circuit by being clipped to the bare metal of the computer case. The wrist strap does not protect the user from receiving an electrical shock from the device, such as a computer monitor.
The wrist strap is designed to protect static-susceptible components, such as motherboards, from destruction by static electricity. Most people have experienced a zap of static electricity when touching another person or a metal object. This electricity usually results from walking across a carpet or rubbing against a static-producing object, such as a balloon. If a person touches an electronic component, the component may short out. Normally, an electronic device's case protects it from electrical shock so that the average user does not destroy the electronics.
Antistatic wrist straps are not designed to protect the wearer from electrical current. Repair technicians who work on monitors and televisions have specialized equipment to dissipate the stored electrical charge in the appliance. An antistatic wrist strap protects electronic components from static electrical charges, which is different from direct current (DC) or alternating current electricity (AC). The shock from an appliance may be deadly.
Electronics manufacturers use special equipment to protect the vulnerable components. An antistatic wrist strap is one of the most common devices, but often it requires the workers to use electrostatic dissipative (ESD) shoes or heel-grounding straps in conjunction with the antistatic wrist straps. Most manufacturers lay special ESD carpeting, have workbench ESD mats, and require ESD smocks. When a person uses the wrist strap alone, she should take as many precautions as possible.
A person can reduce damage from static electricity buildup in a few simple ways. It is helpful to wear 100-percent cotton clothing as well as to keep both feet on the floor while working on the components. When people shuffle their feet, static electricity builds up, so a person should walk carefully or dissipate the built-up static by touching a metal object. Some people use the antistatic wrist straps to dissipate static charge in other ways, such as using it to dissipate the charge that builds up while running on a treadmill. The person simply attaches the strap's alligator clip to the metal of the treadmill to avoid zaps from electrostatic charges.