Does it make any difference on output amperage if output voltage is the sam e in wall plug/USB charger adapters? Referring to 1 amp vs 1.8 amps. Forme r is for iPhone & latter for Kindle Fire HD. Was hoping to use one of thes e adapters rather than having to buy another one for Samsung Intensity II p hone. Both have 5 volts output.
ame in wall plug/USB charger adapters? Referring to 1 amp vs 1.8 amps. For mer is for iPhone & latter for Kindle Fire HD. Was hoping to use one of th ese adapters rather than having to buy another one for Samsung Intensity II phone. Both have 5 volts output.
As long as the replacement has at least as many amps as the original you're OK.
Frank,
The output amperage is the maximum output that your power supply will put out. As long as that amperage exceeds the needs of the powered device, you'll be fine. So, the Kindle 5 v charger will work with the phone. The phone 5v charger may not work with the Kindle and may get hot et c..
Dave M.
Most of the 5 volt "wall warts" with 2.5mm plugs that are made for powering and charging smart phones and tablets are rated at 2 amps or 2,000ma output, at least all those I've seen. I have to order a charger for a tablet that has a 2.5mm plug because that tiny plug is not that common yet as is the ubiquitous 3.5mm plug and is very hard to find locally. O_o
TDD
Amazing, the supply not caught up with the demand. Of course, you can likely find them on Ebay or Amazon.
I think standardizing is a good thing. Less crap in the landfill. I've got several old cell phones, and each comes with a box, manual, batteries, charge plug, and, and, and.
. Christ>
All my Nokia phones can use the same charger unless it has the micro USB plug. ^_^
TDD
Actually it appears that most new cell phones are standardizing on Micro USB. So it is nice to be able to use cig lighter to USB or wall wart to USB chargers and a separate cable, then if you need to hook to a PC you can as well. Only downside is USB current spec is 500 mA and lots of devices can charge faster than that; there's ways around it (connecting two pins together to let the device know that it's plugged into a charger not a PC etc. to select charge rate) but sometimes mixing and matching parts will result in a slower than desired charge rate. I actually had issues with that on an old HTC Evo; when using on the car charger it would discharge faster than it would charge while running a GPS enabled app (Waze, Trapster, Telenav etc.) so if I wanted to use the phone for navigation on a road trip I'd have to carry several spare batteries with me. Haven't had that problem yet on newer Motorola smart phones.
nate
I like the fact that USB with its different size plugs is becoming a standard power/data transmission method but there are still a lot of variations that are maddening. There are adapters for different plug sizes but the way they're wired can be different which I've found to be quite irritating. O_o
TDD
Yes and no.
The manufacturers do some strange things with the data pins to indicate that the device is capable of charging at.
For the iPhone and iPad, 2.0V on both data pins tells the iPhone to charge at 500mA. 2.8V on D- and 2.0V on D+ tells the iPhone to charge at
1000mA. 2.0V on D- and 2.8V on D+ indicates 2000mA and is for the iPad.This system is designed to prevent polyfuses from opening on chargers and computers. If you plugged an iPad into a computer's USB port, and used a cable that tried to trick the iPad into charging at 2000mA, the port would shut down. At 500mA the iPad will charge (at least if it's turned off; if it's on then it will discharge, but more slowly).
The key thing to remember is that Apple devices will NOT charge just with 5V on USB pin 1 and GND on USB pin 4. They _must_ see a DC voltage on pin 2 (D-) and pin 3 (D+). A Google Nexus 7 tablet (at least the first generation) will NOT charge just with 5V on USB pin 1 and GND on USB pin 4, the data pins must be shorted. This applies only for chargers, not for a computer's USB port.
On my Google Nexus 7, unless I short the data pins together it won't charge at all from a USB charger (it will charge at a slow rate from a computer or at a fast rate from the supplied charger). So I made up a bunch of cables with the data wires shorted so I can use a high-current car charger or high-current wall wart. Of course these cables can't be used for data transfer anymore.
The question is, "what does the Kindle HD do with pins 2 & 3? Does it short them together for high speed charging? Or do they have a scheme similar to Apple's? I could not find any information on what Lab126 did regarding this.
He DID say USB charger - and the standard USB A cable fits virtually all of the cahargers from the crappy 500ma chinese junk to the best
2.5 or 3 amp (usb3 - usually) chargers. Big works on small, but small doesn't work on big. Usually you can get away with the small one to charge something bigger if the something bigger is turned off - but don't count on it.
USB2 power (charge) spec is 2 amps.
USB is a standard. Any charger or device with a USB A plug will be wired the same. Then you use a "standard" USB a to usb micro, or mini, or special, cable as required by the device
If only that were true! Well the first part is true, USB is a standard.
The second part is, unfortunately, not true.
What _is_ true, is that the +5 and GND pins will be wired the same. But what often matters is how the data pins are wired. Apple has a specific standard for the data pins based on how much current the charger can supply. Other manufacturers do different things. For example Asus, on the Google Nexus 7, requires that the data pins be shorted together to charge from a charger (not from a PC of course).
It's possible to construct a cable that works, or in some cases, buy a cable that has been modified so the data pins are correctly wired. You can also modify the charger, i.e. .
That's what I've run into. O_o
I hope somebody will produce a jumper box like I have for RS-232/422/xxx for USB so I can get things to function when I'm working on or testing something. ^_^
TDD
USB might be a standard but for chargers everyone has their own twist on the theme. Some USB chargers WILL NOT work with some appliances. Some will assume they're connected to a USB port (.5A) even though the supply is capable of much more. There is a big market in the industry for chips that understand everyone's charging twist (and for those who've figured out how to make this stuff programmable).
That's the nice thing about standards; there are *so* many to choose from. USB is no different (and it's getting worse).
OOPS! Looks like one of my eyeballs was looking in the other direction, the one that works. I overlooked USB and thought it was a 2.5mm round plug like the one that's on the 7" tablet I have but it also has a micro USB connection but I don't think it can get power over it. Premature postification, it happens sometimes to all us guys when we get excited. O_o
TDD
LOL, you're showing your age! I once built one of those RS-232 boxes using comparators and a green and red LED for each channel (prior to the availability of dual color LEDs, though I liked having the third state (no LED on).
I still use serial RS-232 connections for programming and control of some equipment but I've noticed little USB connectors showing up on newer models. Ask a young computer geek about RS-232 and he will look at you like you just handed him a rotary dial telephone. ^_^
TDD
Huh? Even Google says you can use other chargers. You just have to use the correct amperage or you may get a slow or no charge.
"If you're using a charger rated less than the one that came with your tablet, your tablet may charge very slowly, or may not charge at all."
To check I just took 5 random chargers out of the junk drawer and my Nexus 7s (both old and new models) charged from all of them using a generic cable.
You seem to have wasted your time...
Apple is notorious for thumbing it's nose at standards - but even apple uses the data lines as data lines and the power lines as power lines. The "smart charge" feature would only work on apple spec chargers. The "standard" works on computers, using them to charge apple devices because the computer power supply meets the "standard"
You are saying the cable connecting from the charger to the device needs the data pins shorted for the Nexus 7 to accept the charge, or the nexus shorts the data pins to turn on the charger? If it needs the pins shorted for the charger but not for the computer, it sounds like it is controlling the "specific" charger which is not a USB device but uses the USB plug?
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