Properties:

An item specifically designed to absorb and consume surges of voltage such as that resulting across contacts when breaking a circuit having an inductive load or a burst of static across a telephone receiver. It is connected in parallel with the item it is protecting. It may be made up of metallic rectifier cells or semiconductor devices connected back-to-back which may or may not be shunted by a capacitor. It may also be a single rectifier cell or semiconductor device shunted by a capacitor. Excludes metallic rectifiers which are rated for rectifying capabilities and all single unit semiconductor devices not shunted by a capacitor. For items perfoming this function by use of voltage sensitive resistors, see resistor, voltage sensitive. See also cutout disk, protective.