Digital multimeters (testers) are essential multi-function measuring instruments for maintenance inspection, quality control, and fault diagnosis of electrical and electronic equipment in manufacturing sites. They provide basic measurement functions including DC/AC voltage, DC/AC current, resistance, continuity check, and diode testing in a single unit, widely used for electrical system troubleshooting on production lines, control panel inspections, and electronic component characteristic verification. Available in various forms from handheld to benchtop types, CAT safety standard compliant models enable safe measurements in high-voltage environments. Unlike oscilloscopes or dedicated power meters, they are positioned as instruments specialized for general-purpose electrical measurements.