Earth ground意思
"Earth ground" is a term used in electrical and electronic systems to refer to the connection of an electrical circuit to the Earth, typically for safety or functionality reasons. Here are the two main meanings of "earth ground":
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Safety Grounding: In this context, earth ground refers to the practice of connecting the non-insulated conductor of an electrical appliance or device to a conducting object that is buried in the ground. This is done to provide a path for electrical current to flow in the event of an insulation failure, preventing the buildup of dangerous voltages that could cause electric shock. For example, in a household electrical system, the third prong of a power cord is usually connected to the earth ground, ensuring that any electrical leakage from the device is safely directed to the ground.
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Functional Grounding: In electronics, earth ground is often used as a reference point for voltages and currents. It serves as a common return path for electrical currents and can help to minimize noise and interference in sensitive circuits. For instance, in radio systems, the earth ground is used as the reference point for the signal ground, which is essential for proper signal transmission and reception.
In both cases, the goal of earth grounding is to provide a low-impedance path to the Earth, which is essentially an infinite source of electrons and can absorb large amounts of current without significant voltage change. This is crucial for protecting people and equipment from electrical hazards.