DC Buck Converter LM2596 DC-DC Power Module LED Display Power Supply Adjustable Step-Down Converter 4.0~40V Voltage Regulator 1. Features a voltmeter display with ±0.1V accuracy and a measurement range of 4–40V. (Note: Input voltage below 4V will not activate the onboard voltmeter.) 2. Equipped with large tactile 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 saved 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 button again. 4. Includes screw terminal blocks for easy connection without soldering. Wire bonding points are retained for added flexibility. (Input voltage must be at least 1V higher than desired output voltage.) 5. Operates at 150kHz internal oscillation frequency, utilizing 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. How to Calibrate Output Voltage: Step 1: Press the right button until the "OUT" LED is lit, 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 voltage 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. The number of presses needed depends on the current voltage level. Step 3: Press and hold the right button for more than 2 seconds, then release to exit calibration mode. All settings are automatically saved. 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