hi everyone, i've tried to boost 4v (2AH battery) to 5v for charging my smartphone using 555 timer and boost converter circuit with transistor as switch but voltage is boosted upto 30v starting from 12v. so i couldnt get desired 5v. when i connected a 1k resistor as load, voltage droped to 6v but mobile was not drawing any current . i've even tried with different inductors and am using a transistor from broken cfl board.
So can u guyz plz give me idea or circuit ? And also am not sure whether the joule thief c/t will work at this v/g level or not?

 

To charge a phone nowadays you need a 1 amp or more 5 volt charger.
https://www.amazon.com/DROK-Module-...rd_wg=xLkZc&psc=1&refRID=S39DN1VRJD4CK0MBVS02