“If you have a reason not to using booster module, then here is it.
some time you want to using 18650 battery for your project, but the some of them require 5v input to work. you just want to design a circuit with the very little power from the power source.
note: the circuit using resistor pot to control voltage output, so you must turn resistor pot util you get desired output voltage before connect your module to +5v mark from circuit.”