It may be necessary to turn the potentiometer up to 15 times before the output voltage changes This is a boost module, the output voltage must be greater than input voltage Boost voltage to a stable regulated output. Useful for a wide range of applications, such as powering 5V USB devices from a 3.7V lithium cell, powering higher powered electronics from a 12V battery, and a wide range of automotive, electronic, and LED projects Constant voltage regulation The built in voltmeter makes for simple installation and adjustment and helps to monitor the supply or device power. A small button switches the voltmeter between input and output. The XLSEMI XL6009 boost regulator IC has an integrated MOSFET, over-temperature protection, and over-current protection Input: 4.5-32V DC Output Voltage: 5-35V Output Current: 4A (max 3A recommended) 30W Maximum Power 400KHz Switching Frequency