DC Buck Converter LM2596 DC DC Power Module LED Display Power Supply Adjustable Step-Down Converter 4.0~40 V Voltage Regulator 1. Features a voltmeter display with ±0.1V accuracy, measuring range 4~40V. (Note: Input voltage below 4V will not activate the onboard voltmeter.) 2. Large 5x5 touch button switches between input and output voltage measurement, with an indicator light showing the selected mode. Default display shows input voltage with "IN" indicator lit; pressing the button switches to output voltage display with "OUT" indicator lit. Settings are saved even after power cycle. 3. Voltmeter can be turned off by long-pressing the switch for 1 to 4 seconds. Press the button again to turn the display back on. 4. Equipped with screw terminal blocks for easy connection without soldering. Wire bonding points are retained. (Input voltage must be at least 1V higher than the desired output voltage.) 5. Uses 150kHz internal oscillation frequency, part of the second-generation switching voltage regulator technology, offering low power consumption and high efficiency. 6. Input端 includes diode protection to prevent damage from reverse polarity connection. 7. Includes overheat protection and short-circuit protection. (For loads above 15W, additional heat dissipation is recommended.) How to Adjust Output Voltage Accuracy: Step 1: Press the right button until the "OUT" LED lights up, indicating output voltage is displayed. Press and hold the right button for more than 2 seconds, then release. The display and "OUT" LED will flash, entering calibration mode. Step 2: Press the right button to increase the value in small increments; press the left button to decrease. Each press adjusts the value by less than 0.1V. Multiple presses (1–5 times) may be needed for a 0.1V change, depending on current voltage level. Higher voltages require fewer presses per 0.1V change. Step 3: Press and hold the right button for more than 2 seconds, then release to exit calibration mode. All settings are saved automatically. Specifications: Input Voltage: 2.5V~40V Output Voltage: 1.25V~37V (adjustable) Output Current: Up to 3A Conversion Efficiency: Up to 92% Output Ripple: Low noise design