RVM-380V AC Digital Voltmeter Module – 70–380V LED Display

The Compact AC voltmeter 0.56 inch is a compact panel-mount digital AC voltmeter module designed to measure and display AC voltages in the 70V to 380V range. It is a two-wire device: one lead connects to the live (phase) conductor and the other to the neutral line, and the module draws its operating power directly from the measured circuit, eliminating the need for a separate auxiliary power supply. This makes installation straightforward in industrial control panels, workshop distribution boards, and equipment where a dedicated 5V or 12V rail is not available.

The measured voltage is converted from its RMS value into a digital reading and shown on a three-digit 0.56-inch seven-segment LED display, which provides clear visibility from a distance in both bright and dim environments. The module refreshes its reading approximately every 300ms and has a stated allowable error of ±1%, sufficient for general-purpose monitoring and troubleshooting rather than laboratory-grade metrology. Input resistance is greater than 1MΩ, which limits the load placed on the measured circuit. The compact housing measures 48×29×22mm with a 46×27mm panel cutout and weighs only 18g, so it can be fitted into tight panel spaces without significant mechanical support.

Because the module is permanently connected to the mains circuit, appropriate safety precautions are essential: the input must never exceed 380V AC, wiring should be performed with the circuit de-energised, and the installation should comply with local electrical codes. The RVM-380V is intended for continuous voltage monitoring in workshops, industrial control systems, generator and inverter output checks, and general AC mains diagnostics.