because the module was designed without common ground design, so the board can not add diodes, and output capacitors to prevent damage caused by transient over-voltage, so the user in the use of transient high-voltage pulses may exist, or the use of the voltage close to the 35V, it is recommended to follow the screenshot below to add a diode and output capacitors to the module for protection. The voltage drop of the module is about 0.3V at no load or very low load current, and decreases significantly with load currents greater than 10ma (12V test) and is dependent on the amount of current.