Abstract : To ensure the smooth progress of the welding process, as well as to guarantee excellent welding performance and welding quality, increasingly higher requirements are placed on the detection of arc welding power sources, a special type of power supply. The traditional method of manually recording the external characteristic data of arc welding power sources is no longer adequate for the needs of development. Therefore, an advanced detection method is urgently needed to monitor changes in the external characteristics of arc welding power sources in real time. This paper uses LabWindows/CVI software as the software development platform to program the Advantech PCI-1710 data acquisition card, thereby designing a system for acquiring the external characteristic current signal of arc welding power sources. This system can accurately detect changes in the current signal output by the arc welding power source in real time. Keywords : External characteristics of arc welding power source; Detection system; LabWindows/CVI 0. Introduction Arc welding technology is an important component of modern welding technology, and its application scope covers almost all welding production fields. Arc welding power sources are special power sources, and their external characteristic shape not only affects the stability of the "power source-arc" system and welding specifications, but also relates to the arc ignition performance, droplet transfer, and safety of use. To ensure smooth welding processes and guarantee excellent welding performance and quality, increasingly stringent requirements are being placed on the testing of arc welding power sources, a special type of power supply. The traditional method of manually recording the external characteristic data of arc welding power sources is no longer adequate. Therefore, an advanced testing method is urgently needed to monitor changes in the external characteristics of arc welding power sources in real time. To facilitate understanding of the external characteristics of arc welding power sources, a data acquisition system was designed to describe the external characteristic current signal of the arc welding power source. This system utilizes the LabWindows/CVI programming language to accurately and quickly display the external characteristics of the arc welding power source visually and store the external characteristic current signal of the tested power source for later data processing. [Full text download of "Current Signal Detection System for External Characteristics of Arc Welding Power Sources Based on Virtual Instruments"]