Power (3-40V), power indicator light, the module is working properly Adjust the blue potentiometer knob (clockwise rotation generally boost,counter-clockwise rotationTurn down) and reach with a multimeter to monitor the output voltage required voltage Current work long hours is recommended for use in less than 2.5A, while adding bulkHeat sink (10W output above),because it is the step-down module, in order to ensure stable output Set,please keep the minimum 1.5V differential A power adapter module for electronic devices. When a device requires power-and a power source of the appropriate voltage is already available-you can use this module to easily adjust the voltage to the level required, thereby resolving power supply issues and facilitating the testing of the system's operating voltage. You only need to connect the input terminal of this module to the car cigarette lighter for power supply, then you can adjust the potentiometer, and the output voltage can be adjusted arbitrarily between 1.25-30V to power your mobile phone, MP3, MP4, PSP charging and many other devices. It is very simple and convenient Name : LM2596 DC-DC Buck module Input voltage :4V ~ 35V The output voltage : 1.23V ~ 30V Output Current :3A( Max) Conversion efficiency:92%( MAX ) Output ripple: <30mV Switching frequency: 150KHz Working temperature: -forty Five~ +85 Connection mode:1. Welding: welding the power cord directly to the input (output) port; 2.Welding pin,which can be inserted into the pin through the lead or inserted into the hole board for use; Or solder directly on PCB after adding pins Color: As Shown Material: PCB Package Contents: 2*DC-DC Step Down Power Supply Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.