High-voltage error detection protecting method of avometer and avometer

Abstract

The invention provides a high-voltage error detection protecting method of an avometer. The method is characterized by comprising the following steps that: 1) a composite reactive protecting circuit is connected in series between an input terminal and a multi-channel function switching switch, wherein the protecting circuit consists of at least one positive temperature coefficient (PTC) element and a low-voltage fuse element connected in series with the PTC element, the PTC element is quick in voltage division response and high voltage resistant, the low-voltage fuse element is slow in voltage division response, and the highest overload current value of the PTC element is less than the set fusing current value of a low-voltage fuse; and 2) when the input terminal mistakenly detects high voltage which is 600V or higher, the internal resistance of the PTC element is quickly increased to prevent instant increase of loop current and share a large part of voltage, the low-voltage fuse shares a small part of voltage and is fused when the set fuse current value is reached, and a power supply is cut off, so the PTC element is always in the highest overload current range and is not exploded or damaged by current overload, and a circuit arranged behind the multi-channel function switching switch is protected at the same time. The invention also provides the avometer for implementing the method.

Description

technical field [0001] The invention relates to the technical field of electronic measuring tools, in particular to a multimeter high voltage misdetection protection method and a multimeter which use a composite reaction type protection circuit to realize high voltage misdetection protection. Background technique [0002] At present, the electronics industry has launched a variety of protection devices, including low-voltage fuses FUSE, self-resetting PTC, polymer PTC self-resetting fuses and bimetallic strips. Then you can restore yourself. When it operates, it generates a large voltage and reconnects the fault that may damage the equipment. The polymer PTC resettable fuse will always be in a high resistance state until the fault is eliminated. The application of these devices is basically used alone according to its characteristics, but according to the latest safety standard IEC61010-2-030:2010, the following safety hazards will occur when the instrument misdetects high...

AI Technical Summary

Problems solved by technology

However, when used alone, due to its own overload current limit, it will cause its own explosive failure, which will also bring safety hazards to the protection.

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