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. Equipped with large touch buttons to switch between input and output voltage measurement. An indicator light shows which voltage is being measured. By default, the display shows input voltage with the IN indicator lit. Pressing the button switches to output voltage display with the OUT indicator lit. Settings are retained even after power cycle. 3. Voltmeter can be turned off by pressing and holding the switch for more than 1 second but less than 4 seconds. To reactivate, simply press the switch briefly. 4. Includes screw terminal blocks for easy connection without soldering. Wire bonding points are preserved. (Input voltage must be at least 1V higher than desired output voltage.) 5. Operates at 150kHz internal switching frequency, featuring second-generation switching regulator technology for low power consumption and high efficiency. 6. Input端 includes diode protection to prevent damage from reverse polarity connection. 7. Built-in overheat and short-circuit protection. For loads exceeding 15W, additional heat dissipation is recommended. Output Voltage (or Input Voltage) Calibration Steps: Step 1: Press the right button until the "OUT" ("IN") LED lights up, indicating output (input) voltage is displayed. Hold the right button for over 2 seconds, then release. The display and 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. Due to resolution limits, multiple presses (1–5 times) may be required to observe a 0.1V change on the display. Higher voltages require fewer presses per 0.1V change. Step 3: Hold the right button for over 2 seconds 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