Adjustable buck-boost module: voltage range is DC 5.5-30V; Output voltage range is DC 0.5-30V, can be arbitrary adjustable; The output current range is 0-3A, can be arbitrary adjustable, if enhance heat dissipation, it can reach 4A; The output power can up to 35W, if enhance dissipation, it can reach 50W. With protection function: the volt transformer board is with reverse connection protection at input terminal, reverse connection will not burn; Stop the current from feeding back protection at output terminal; Short circuit protection; Backflow prevention at the output, when charging the battery, there is no need to add a second anti-backflow tube. Bright LCD display: the voltage regulator module is designed with LCD, can display input and output voltage, output current and output power; Voltage display resolution is 0.05V, current display resolution is 0.005A; Low output ripple, with LC filter Button control: the IN/ OUT button switches the display of input voltage and output voltage; Long press can switch the display of output current and output power; the ON/OFF button controls the output ON or OFF; Long press can set the default output state of the next power-on to ON or OFF. Application: the switching power supply can be applied as an ordinary buck-boost module with over-current protection; Serve as a battery charger or a high-power LED constant current driver module Features: 1. The module has IN/OUT and ON/OFF buttons: IN/OUT button switches the display of input voltage and output voltage, long press can switch output current and output power display; ON/OFF button controls output ON or OFF, long press can Set the default output state of the next power-on to ON or OFF. 2. CC is the current setting potentiometer. Turn clockwise to increase the setting current. When the load current is set to the current, it enters the constant current state,and the CC constant current indicator (red) lights up; the right CV is the voltage setting potential The output voltage