yesterday i try to use DC power supply set the output as 6v 0.3A at lab,it can charge cell phone,if set it as 5.5v,it cannot charge.
so, have any circuit possible to step up the 5V 0.3A to 6V 0.3A???
you would need an inverter sicrcuit that for this simple situation is silly. if you have a transformer you can create a doubling rectifier that will double the voltage of the transformer when rectified but as audioguru said you cannot creat energy so you will have half the amperage ie 150 mA
acording to P=V.I,if 6v 300mA get 1.8w,then can charge the phone
then i change the output as 5v 360mA, also is 1.8w,y i cannot charge the phone?
then i change the output as 6.5v 270mA, get nearly 1.8w,also cannot charge the phone,y??
can someone teach me