The human-body-model (HBM) describes the discharge of an electrostatically charged human body via a grounded component. It assumes the discharge to be triggered by contact of any pin of the component, while any other pin of the same component is grounded. In this connection, "pin" has to be understood as any metallic conductive surface of a component, which does not only include actual pins but e.g. also metallic heat slugs.
The HBM is especially important for the manual assembly of discrete and integrated semiconductor devices on printed circuit boards (PCB). It was developed driven by an increasing number of ESD failures of these devices in the 1960s and 1970s and was standardized as the very first ESD model in the beginning of the 1980s. In the course of the miniaturization of semiconductor devices and advancing automation of the PCB assembly, the HBM has meanwhile lost its initial significance in favor of the charged-device model (CDM).