Method of detecting whether AC earth wire is well connected

Abstract

The invention discloses a method of detecting whether an AC earth wire is well connected. The method of detecting whether an AC earth wire is well connected is based on an improved earth wire detection circuit, and the improved earth wire detection circuit comprises a triode Q1, an optical coupler U1, resistors, diodes, voltage-stabilizer tubes and the like, wherein a first terminal (1), a second terminal (2), a third terminal (3) and a fourth terminal (4) are arranged on the circuit; and by determining the level output of the fourth terminal (4), the method can be applied to various electronic devices to determine whether an earth wire is connected correctly and reliably, wherein when a live wire and a zero wire are inversely connected or the earth wire and the live wire are inversely connected, the connection state of the earth wire can be detected; and when an electrified device grounding circuit exceeds certain voltage or the resistance to earth is too large, the connection state of the earth wire can also be detected.

Description

technical field [0001] The invention relates to the technology in the field of electronic circuits, in particular to a method for detecting whether the connection of an AC ground wire is good. Background technique [0002] At present, the first commonly used simple ground wire detection circuit is shown in figure 1 , through the voltage difference between the live wire and the ground wire, a certain current is formed through the resistor R1, and then the optocoupler U1 is triggered, and a square wave output is detected at the Earth-Test terminal through the single-chip microcomputer. At present, the second commonly used simple ground wire detection circuit is shown in figure 2 ,and figure 1 Compared with the circuit, it does not need single-chip microcomputer control, and directly replaces the optocoupler with an LED. When the ground wire is in good contact, the LED will light up. [0003] The detection methods of these two detection circuits judge whether the ground con...

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Problems solved by technology

However, when the ground line is charged or has a certain resistance to the ground, a loop can also be formed between the live line and the neutral line, and a certain current will be generated to trigger the optocoupler U1 or directly light up the LED light, resulting in a When the ground resistance value is too large, it cannot be reliably detected, and there is a defect of unreliable detection

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