I have been reading a lot over the last week about usb chargers and how they work, on an use 2.0 connector there are 4 pins 1 + 4 are for power, the two center ones are for data like when you connect to your computer, I read that a lot of manufactures put a resistor across pin 2 and 3 connecting them together this is how tablets/phones detect if they are connected to a good usb adapter that has fast charge, so the tablet can pull as much power from the usb adapter as it needs, I measured pins 2 and 3 on my Samsung usb adapter and it reads 1 ohm, so then i checked all my usb adapters and about 4 out of 10 read as 1 ohm and my S1 charges at the maximum current of the adapter.
I have two third-party 2.1 amp usb mains chargers, and they only charge my S1 at 600ma so i measured pins 2 and 3 and they are like 50k , I bought this usb adapter or years ago for my Samsung phones, you just plug it into the charging socket of an third-party adapter and it is supposed to trick the Samsung phone into charging at full speed, I just measured the resistance across pins 2 and 3 and it is 1 ohm, so i plugged the adapter into one of the 2.1amp third-party adapters that only charge my S1 at 600ma, as soon as i used the adapter my S1 started charging at 1400ma, So it looks like i am onto something here.
Supposedly different manufactures put different resistances across pins 2 and 3 so they can detect one of their adapters and charge at full speed.
I also read that apple puts the resistor in the usb cable not the usb adapter, but i don't have an apple adapter or cable so i cannot check if this is correct.
John.
I have two third-party 2.1 amp usb mains chargers, and they only charge my S1 at 600ma so i measured pins 2 and 3 and they are like 50k , I bought this usb adapter or years ago for my Samsung phones, you just plug it into the charging socket of an third-party adapter and it is supposed to trick the Samsung phone into charging at full speed, I just measured the resistance across pins 2 and 3 and it is 1 ohm, so i plugged the adapter into one of the 2.1amp third-party adapters that only charge my S1 at 600ma, as soon as i used the adapter my S1 started charging at 1400ma, So it looks like i am onto something here.
Supposedly different manufactures put different resistances across pins 2 and 3 so they can detect one of their adapters and charge at full speed.
I also read that apple puts the resistor in the usb cable not the usb adapter, but i don't have an apple adapter or cable so i cannot check if this is correct.
John.
No comments:
Post a Comment