Buck-Boost Converter, DROK Numerical Control Step Up Down Voltage Regulator Board DC 10V-40V 12v 24v 36v to 0-38V 5v 9v 6A 240W Volt Transformer, Variable DC Power Supply Module It's a fully digital display numerical control cc cv buck boost module, which adopts advanced microprocessor, can regulate output Voltage and current accurately, has high efficiency and Stable performance; the input Voltage can be lower or higher than the output Voltage, also can be the same as the output Voltage. The voltage converter module has two kinds of modes: simple mode and fully functional mode(simple mode by Default); uses 4 digits high Brightness LED, can display output Voltage, current, power and capacity and other parameters; has out, cc, cv indicators and memory saving function, can store 10 Groups of parameters and they can be freely stored and called out. Simple mode: after setting the Voltage and current values, pressing "OK" the module will output, then use the "" "" buttons to increase or decrease the value at output statue, short press "OK" to switch between Voltage and current display, long press for 3 seconds to turn on/off the function of displaying Volt and amp in turns. Under fully functional mode, there are three special functions: 0 output automatically when power on; 1 save and call out the parameters, display power and capacity; 2 take turns to show the parameters after output automatically you can open them by yourself. The step up down board is perfect for electronic hobbyists and suitable for wind power, DC generator, solar panels to charge battery, you can also make your own power supply to power up devices; please connect wires correctly and enhance heat dissipate when the output current is over 5A.