POWERED VOLTAGE MONITORING: This Buck Converter Module includes a power indicator and a voltmeter with selfcalibration. It uses an advanced voltage microprocessor; voltmeter error is ±0.05V and the measurement range is 040V. Note: To ensure the accuracy of the voltmeter, please ensure that the input voltage is above 4.5V. PERFORMANCE MEASUREMENT: Touch the button to switch between measuring the input voltage or the output voltage. An indicator light shows which voltage is being measured, and the selection is saved automatically, even after power is turned off and on again. ADVANTAGE AND PROTECTION: The voltmeter can be turned off by tapping the left button when not needed. The module includes overheating protection and shortcircuit protection for safer operation. EASY TO USE DESIGN: Step Down Module with terminal blocks for simple wiring. No soldering is required, and wire connection points are reserved for convenient connections. SPECIFICATIONS AND COMPATIBILITY: 040V measurement range, voltmeter accuracy ±0.05V, input voltage for accurate readings should be above 4.5V. Suitable for use with buck converter setups and related DC power projects requiring reliable input and output voltage monitoring. USE SCENARIOS: Use in power supply testing to monitor both input and output voltages of a buck regulator while adjusting settings. Batterypowered projects up to 40V that require quick voltage checks without disassembly or soldering. DIY electronics experiments where easy wiring and persistent measurement settings improve workflow.