## Overview of the DMS-20RM-2-DC2-R-C The **DMS-20RM-2-DC2-R-C** is a high-precision, digital RMS (Root Mean Square) AC voltmeter designed and manufactured by **Murata Power Solutions**. It is specifically engineered to measure the true RMS voltage of complex AC waveforms, such as those generated by switching power supplies or motor controllers. --- ### Key Specifications | Parameter | Specification | | :--- | :--- | | **Part Series** | DMS-20RM (RMS Voltage Monitor) | | **Input Voltage Range** | 0 to 199.9 Volts AC (True RMS) | | **Operating Power Supply** | +4.5 to +5.5 Volts DC | | **Display Color** | Red (High Intensity) | | **Display Type** | 3½ Digit LED (8mm height) | | **Accuracy** | ±0.5% of reading + 2 counts | | **Package Style** | 12-pin DIP (Miniature encapsulated) | | **Operating Temperature** | 0°C to +60°C | --- ### Component Breakdown & Features #### 1. Internal True RMS-to-DC Converter Unlike standard "average-responding" meters, this part includes specialized circuitry to calculate the True RMS value. This means it accurately measures waveforms that are not perfect sine waves (e.g., square waves, triangular waves, or "noisy" AC lines). #### 2. Self-Contained Design The module is encapsulated in a rugged, moisture-resistant epoxy plastic package. It functions as a complete "plug-and-play" system requiring minimal external components (typically just a power source and the input signal). #### 3. Low Power Consumption Despite the bright LED display, the unit is highly efficient, typically drawing only **40-60mA** from the 5V DC supply, making it suitable for portable or battery-powered test equipment. #### 4. Pin Configuration The device uses a 12-pin DIP layout. Key pins include: * **AC Input (High/Low):** Where the measured AC signal is connected. * **+5V DC Power:** The regulated power source for the internal electronics. * **GND:** Common return for the power supply. --- ### Part Number Nomenclature (Decoding) | Suffix | Meaning | | :--- | :--- | | **DMS-20RM** | Digital Meter Series - RMS Voltmeter | | **2** | Input Range (2 = 200V range) | | **DC2** | Power Source (DC2 = +5V DC) | | **R** | Display Color (Red) | | **C** | RoHS Compliant | --- ### Common Applications * **Industrial Automation:** Monitoring AC line voltages in control panels. * **Power Distribution Units (PDUs):** Real-time monitoring of server rack power. * **Alternative Energy:** Measuring output from DC-to-AC inverters. * **Test Equipment:** Integration into custom bench-top measurement tools.