HTC One M9 Camera Fails In Tests

HTC One M9 Camera Fails In Tests: It's Worse Than A Three-Year-Old iPhone 4S

HTC has a problem, and it’s a problem it has had for some time now – failing sales. Even with Cher Wang replacing Peter Chou as leader of the company she founded, the firm has yet to find its feet. One of its biggest problems is that despite very competent hardware design, its phones are let down by a distinct lack of excitement. Its next biggest problem is the fussy UI design that comes from its Sense user interface. While the One M9 was an improvement over the M8, the difference was very slight but the new phone costs considerably more.

But HTC’s problems have worsened again with imaging experts DxOMark declaring its camera worse than the iPhone 4S and Samsung Galaxy S3 phones which are three and two-years-old respectively. That has to be seen as a problem for HTC, but first let’s take a look at some background to see how it ended up here.

HTC’s One M9 replaces the dual-camera of the M8, but with little quality increase

The big difference between the M8 and M9 was the camera, which HTC swapped from the dual sensor in the M8 to a higher megapixel version in the M9. HTC touted the dual-camera sensor as a huge advancement in cameraphones, but the truth was quite different. The 4-megapixel cameras just couldn’t keep pace with the sensors in every other camera.

And perhaps worse still, the advantages of the dual sensor were supposed to be that you could re-focus the shots after taking them, but this was so easily duplicated with a software solution that pretty much every phone with one sensor was able to do much the same process in software. And it was this that eventually led HTC to abandon the sensor and move to a 20-megapixel model. That sensor puts it close to phones like Sony’s Z3 20.7-megapixel model, and way in advance of other camera sensors, which tend to come in at around 16-megapixels. But, HTC also forgot one other thing that most other companies have included – stabilization. This is crucial in small, light phones which are easily moved and it plays a huge part in boosting the quality of images taken in poor light, allowing the phone to slow the shutter to allow in more light, while keeping the image free of shake and blur.

At 20-megapixels, this is one of the highest-specified cameras on a phone, but the results just don’t meet expectations

In their findings, the team at DxOMark said that in good light, everything was great – with good colour, detail and with the autofocus performing well. Sadly, in lower light conditions that all changes and everything becomes disappointing with them noting that colours are oversaturated and that there’s a loss of sharpness. They then give the HTC One M9 a camera score of 69.

In contrast, they rate the Samsung Galaxy S6 Edge as having the best camera, scoring 86 while the Note 4 grabs second place with 83.The iPhone 6 and 6 Plus assume the third and fourth positions with 82 points. The M9 scores the same as Amazon’s Fire Phone, but is still beaten by phones like the Note 2, Galaxy S3 and LG’s G2.

Worst of all though, HTC only just manages to beat the result of the M8, which scored 68 when tested. That’s a massive problem for a phone costing nearly twice as much money, and with scant other features to sell itself on.

With the announcement that HTC is partnering with Valve for that company’s VR offering, called Vive, perhaps the company is looking for an exit from mobiles. It isn’t a diverse company in terms of investments, so it needs to do something to shore-up disappointing sales. Unsurprisingly though, the HTC Re camera was pretty much universally panned for below-average image quality, so the firm doesn’t have a great track-record outside of phones.

Whatever HTC’s longterm chances of survival are, the message from DxOMark is simple: don’t buy an HTC One M9 for the camera.

HTC One M9 Camera Fails In Tests

9:47 AM android, Apple, HTC ONE M9, Iphone, phone camera, smart phones

HTC One M9 Camera Fails In Tests

HTC One M9 Camera Fails In Tests: It's Worse Than A Three-Year-Old iPhone 4S

HTC has a problem, and it’s a problem it has had for some time now – failing sales. Even with Cher Wang replacing Peter Chou as leader of the company she founded, the firm has yet to find its feet. One of its biggest problems is that despite very competent hardware design, its phones are let down by a distinct lack of excitement. Its next biggest problem is the fussy UI design that comes from its Sense user interface. While the One M9 was an improvement over the M8, the difference was very slight but the new phone costs considerably more.

But HTC’s problems have worsened again with imaging experts DxOMark declaring its camera worse than the iPhone 4S and Samsung Galaxy S3 phones which are three and two-years-old respectively. That has to be seen as a problem for HTC, but first let’s take a look at some background to see how it ended up here.

HTC’s One M9 replaces the dual-camera of the M8, but with little quality increase

The big difference between the M8 and M9 was the camera, which HTC swapped from the dual sensor in the M8 to a higher megapixel version in the M9. HTC touted the dual-camera sensor as a huge advancement in cameraphones, but the truth was quite different. The 4-megapixel cameras just couldn’t keep pace with the sensors in every other camera.

And perhaps worse still, the advantages of the dual sensor were supposed to be that you could re-focus the shots after taking them, but this was so easily duplicated with a software solution that pretty much every phone with one sensor was able to do much the same process in software. And it was this that eventually led HTC to abandon the sensor and move to a 20-megapixel model. That sensor puts it close to phones like Sony’s Z3 20.7-megapixel model, and way in advance of other camera sensors, which tend to come in at around 16-megapixels. But, HTC also forgot one other thing that most other companies have included – stabilization. This is crucial in small, light phones which are easily moved and it plays a huge part in boosting the quality of images taken in poor light, allowing the phone to slow the shutter to allow in more light, while keeping the image free of shake and blur.

At 20-megapixels, this is one of the highest-specified cameras on a phone, but the results just don’t meet expectations

In their findings, the team at DxOMark said that in good light, everything was great – with good colour, detail and with the autofocus performing well. Sadly, in lower light conditions that all changes and everything becomes disappointing with them noting that colours are oversaturated and that there’s a loss of sharpness. They then give the HTC One M9 a camera score of 69.

In contrast, they rate the Samsung Galaxy S6 Edge as having the best camera, scoring 86 while the Note 4 grabs second place with 83.The iPhone 6 and 6 Plus assume the third and fourth positions with 82 points. The M9 scores the same as Amazon’s Fire Phone, but is still beaten by phones like the Note 2, Galaxy S3 and LG’s G2.

Worst of all though, HTC only just manages to beat the result of the M8, which scored 68 when tested. That’s a massive problem for a phone costing nearly twice as much money, and with scant other features to sell itself on.

With the announcement that HTC is partnering with Valve for that company’s VR offering, called Vive, perhaps the company is looking for an exit from mobiles. It isn’t a diverse company in terms of investments, so it needs to do something to shore-up disappointing sales. Unsurprisingly though, the HTC Re camera was pretty much universally panned for below-average image quality, so the firm doesn’t have a great track-record outside of phones.

Whatever HTC’s longterm chances of survival are, the message from DxOMark is simple: don’t buy an HTC One M9 for the camera.

HTC One M9 Camera Fails In Tests

9:47 AM android, Apple, HTC ONE M9, Iphone, phone camera, smart phones

Apple's new battery reveled!

APPLE’S HUGEST REVEAL THIS WEEK: THOSE CRAZY NEW BATTERIES

Apple

THE MOST EXCITING Apple announcement this week wasn’t a $10,000 smartwatch or a new, gold-colored MacBook. It was a battery technology that could have major implications for how long all future Apple products last between charges—including your next iPhone.

Apple’s battery breakthrough is already paying dividends in Apple’s super-slender MacBook. In order to achieve that 13.1 mm silhouette—and still deliver reasonable battery life while powering a 12-inch Retina display—the company’s engineers had to develop something entirely new. What they came up with is a terraced battery cell, a unique design that adds 35 percent more battery capacity than would otherwise be achievable.

“It might seem like a low level innovation, but it’s an incredibly clever design,” Jeff Chamberlain, executive director of the Joint Center for Energy Storage Research, told WIRED. In fact, it’s a whole new way of thinking about batteries.

Rethinking the Battery

A typical lithium ion battery “pouch” type cell comprises layers of a thin sheet of aluminum or copper, coatings of a specialized material that can absorb lithium ions, and layers of plastic. Each of these layers is mere microns thick.

What Apple has figured out, according to a patent filed back in early 2012, is how to fit these stacked electrode sheets into any size cell they choose. These different-sized cells can then be stacked on top of one another, allowing its engineers to pack as much battery as possible into any given space.

In order to assemble the terraced battery cells in the MacBook, Apple says it used high speed cameras to take photos of the casing and the battery. This process documents the minute variations in each that occur during real-world production, so that Apple can fit the batteries inside each individual casing with an unprecedented degree of precision.

Apple also—according to what it said during its Monday keynote—tweaked the chemical formula inside the cells. That didn’t have any bearing on the unique battery shape, but by altering the composition, Apple could eke a little bit more efficiency over previous MacBook batteries.

Apple lists the MacBook has achieving up to nine hours of battery life. That may sounds relatively paltry—the 13-inch Air gets 12-hours of battery power—until you consider that it has to push power to a Retina display’s huge number of pixels. The 13-inch MacBook Pro with Retina gets 10 hours of battery life, and the 15-inch model gets eight hours. In a form factor that’s 1.5 pounds lighter and .2 inches thinner (at its thickest point), the MacBook lasts comparably long. That’s impressive, even when you also consider its power-sipping Core M processor.

An Adaptable Innovation

What’s even more exciting, though, is that while the MacBook is the first consumer product to use this new battery technology, we’re sure to see it applied to other iDevices. Apple’s tick-tock upgrade cycle for the iPhone normally leaves minimal hardware changes for the “tock” models (the “S” versions, like the iPhone 4s and 5S). But with the iPhone 6 and 6 Plus’s contoured exterior, it’s not a stretch that this year’s S model could include the new battery tech. The beefed up battery design could also easily make its way into the iPad line, and into future MacBook Airs or MacBook Pros (both of which only saw minimal updates during Monday’s event).

Even if we don’t see this tech applied to new products immediately, we will undoubtedly see it at some point. iFixit’s Kyle Wiens says that one of the most important results of this battery innovation is its implications on product design across a whole range of devices.

“It frees the industrial designers to be able to design what they want, and then fit the battery in after the fact, rather than creating the design around the battery,” Wiens told WIRED. Until now, hardware designers have been a slave to the battery size required of a particular device, and forced to build a rectangle, or rounded rectangle, around that.

So, naturally, Apple engineered a new design that frees Jony Ive and team to let their imaginations run wild with possibilities. In addition to the rectangular layers we see in the MacBook, this terraced battery could also theoretically work in circular, triangular, and other shaped spaces. That’s not to say we’re ever going to see a trapezoidal iPad. But at the very least, it enables unconventional thought, like contouring the battery around the spot where the Macbook’s rubberized black feet attach to the notebook (which Apple did).

The redesigned battery also doesn’t sacrifice overall longevity; the new MacBook will survive around 1,000 charges, just like all other Apple laptops. The one caveat would be that this is a proprietary battery, so it will be difficult, if not impossible, to replace yourself, should it wimp out before you’re ready to buy a new notebook. Then again, it’s not like Apple makes it easy to replace your battery anyway.

Eventually, some crazy newinnovation in mobile energy storagewill come along and end all our lithium ion woes. That could be a long way off, though. And the fact that Apple’s not content to sit around waiting for it could end up giving its devices—and you—more battery life relief than you could have imagined

Apple's new battery reveled!

12:42 PM apple battery, battery health, featured, Iphone, mac book, new battery, smart phones, thinnest battery

PIN lock and other updates to Outlook for iOS and Android

Just over two weeks ago, we delivered the first version of Outlook for iOS and Android devices. We’ve heard from many of you that enjoy how Outlook brings together the core tools you need to get things done—your email, calendar, contacts and files—helping you get more done even on the smallest screen.

We promised to deliver updates to Outlook every few weeks and we’ve been listening closely to your feedback. Today, we are happy to share some of the features we’ve added over the past two weeks.

IT controls

While our first release focused on bringing a great end-user experience to market, we are also well underway building the IT controls that our business customers require.

PIN lock

Outlook now implements password enforcement using Exchange ActiveSync. If your company email policy requires that devices have a password in order to sync mail, Outlook will enforce this at the device level. How this works on iOS and Android devices varies slightly, based on the available controls provided by Apple and Google.

On iOS devices, Outlook will check to make sure a passcode is properly set. In the event a passcode is not set, it will prompt users to set one up in iOS settings. Until the passcode is setup, the user will be unable to access Outlook.

Outlook for iOS only runs on iOS 8.0 or later. These devices are shipped with built-in encryption, which Outlook uses once the passcode is enabled to encrypt all the data Outlook stores locally on the device. Therefore, iOS devices will be encrypted whether the Office 365 or Exchange policy requires this or not.

Outlook for iOS enforces simple passcode. Encryption is enabled by default.

On Android devices, Outlook will enforce screen lock rules. Further, Google provides controls that allow Outlook to honor additional Office 365 and Exchange policies regarding password length and complexity requirements and the number of allowable screen-unlock attempts before wiping the phone. It will also encourage storage encryption if it is not enabled. Outlook will guide users through this process with a step-by-step walkthrough.

Devices that do not support these security settings will not be able to connect to an account.

Outlook for Android enforces passwords including length and complexity requirements, storage encryption and will monitor screen-unlock attempts to prevent un-authorized access.

Quicker remote wipe execution

We’ve also made improvements to how quickly admin-led remote wipes are executed—they now happen within seconds. As before, this is an app-level wipe, not a device wipe. The Outlook app will reset and Outlook email, calendar, contacts and files data will be removed from the device, as well as from Outlook’s cloud components. The wipe will not affect any of the user’s personal apps and information.

User-focused features

We’ve also delivered on several of the top feature requests we’ve received in the past two weeks.

IMAP support

Outlook now supports the ability to sync mail from email providers that support IMAP, like AOL.com and Comcast.net. We use IDLE whenever possible, which means Outlook can provide push-like behavior even with IMAP accounts. If the IMAP server doesn’t support IDLE, Outlook will sync every few minutes.

Outlook now connects to email services that support IMAP.

Toggle conversation view for iOS

By default, Outlook organizes your email into conversations, where all messages with the same subject line are grouped together. In iOS, you can now turn this feature off if you’d prefer to see each email individually in your mailbox. Just go toSettings > Organize Mail by Thread and adjust the toggle to match your desired preference.

Use ‘Organize Mail by Thread’ to toggle conversation view on/off.

We expect to bring this capability to Android soon.

Customize swipe gestures on Android

Outlook’s swipe gestures make rapid email triage literally a one touch experience. You can swipe right or left to take actions like archive, delete, move, flag, mark as read/unread or schedule. Unlike other email apps, Outlook lets you personalize these swipe gestures to match your unique email habits. Customization was previously only available on iOS, and is now available on Android.

Go to Settings > Swipe Options to customize your swipe gestures.

Customize your swipe gestures to match your email habits in Settings.

Change folders for swipe gestures

For the Archive and Schedule swipe gestures, you can now choose and change your default folders at any time. Previously, Outlook prompted you to choose a folder for these actions during first use. Now when your email habits change, you can adjust these by going to Settings > Choose an account > Advanced Settings > System Folders.

Set your Archive folder and change it later if necessary in Settings.

What’s next?

Over the coming weeks and months, we will deliver additional security and management features that matter to IT as well as user-focused features to help you get even more done while on the go.

Coming IT controls:

Support for Microsoft Intune mobile device managementMoving Outlook’s cloud service from Amazon Web Service to Microsoft Azure

Coming user-focused features:

Support local syncing of contactsRemoving ‘Preview’ label from Outlook for AndroidImproving localization for all 30 supported languages

In addition to feature improvements, we are working on adding more documentation about Outlook’s architecture, security, and administrative controls. For now, you can read Javier Soltero’s post about these topics in our Office 365 Network on Yammer. The Outlook product team also recently held a YamJam to discuss these topics. If you couldn’t join us, read the summary here.

Have a feature request? Let us know right from Outlook by navigating to Settings > Help > Contact Support, as this will help us triage and prioritize.

Stay tuned for much more to come!

Frequently asked questions

Q. The native Mail application on iOS enforces Office 365 and Exchange policies for password length and complexity requirements. Why doesn’t Outlook?

A. Outlook takes advantage of the controls available to Microsoft as a 3rd party application developer. As we enable support for Microsoft Intune mobile device management and as Apple makes more controls available, we will continue to improve this capability.

Q. OWA for iPhone/iPad/Android enforced PIN lock at the app-level. Why is Outlook enforcing PIN at the device level?

A. After talking with our customers and evaluating iOS and Android capabilities, we believe a device-level PIN is the best experience for customers for both convenience and security. An app-level PIN means you often have to enter two different PINs in order to access your email, which is cumbersome. Further, a device level PIN means we can take advantage of features like native device encryption, TouchID on iOS and Smart Lock on Android. Remote Wipe is still implemented at the app-level, which means your personal applications and data will be unaffected when Outlook is wiped. We will evaluate this approach in response to your feedback and as we enable support for Microsoft Intune mobile device management.

PIN lock and other updates to Outlook for iOS and Android

8:55 AM android, ios, ipad, Iphone, Microsoft, OUTLOOK, PIN LOCKER

How to tell if your smartphone's battery is healthy or bad

A smartphone without a battery is like a time machine without a 1.21-gigawatt nuclear power source. In other words, it is useless – the battery is what provides that magic juice every smartphone needs to operate. 

Unfortunately, even if you take good care of your smartphone's battery, it will inevitably degrade over time and lose some of its charge capacity. At that point, it might be hard to tell if the cell is still in good health or in need of a replacement. That's why we thought we'd share a few tips on the matter.

Perform a visual inspection

You don't need to be a rocket scientist to tell a faulty battery from a healthy one. In fact, some common battery failures are easy to spot with a naked eye. If the battery of your phone is removable, simply take it obut with caution (after turning the phone off, of course) and look for symptoms like bulging, corrosion near the metal terminals, and green or white-ish stains. These are all signs that the cell is about to kick the bucket. If you don't see anything wrong with it, proceed to the next tip. If you find suspicious stains or if your cell has developed a hump, however, it is a good idea to ask your carrier or vendor for advice as your battery most likely needs to be replaced. Don't put the old cell back inside the phone as you don't want it leaking any nasty chemicals; these may damage the phone's circuitry. Instead, seal the battery in a plastic zip bag and make sure you recycle it once it is confirmed to be faulty by a professional.

Do a spin Test Of Your Battery

Your battery should not spin like this

Lithium-based batteries degrade with each discharge cycle. Not storing them properly makes matters even worse – extreme heat or cold may seriously shorten their lifespan. Another way to ruin a perfectly good battery is to drain it and leave it with no charge for a long time. Eventually, a battery might swell if not treated with care. This swelling happens slowly, usually over the course of weeks and even months, which is why a hump that has just started forming on the battery's side can be pretty hard to notice. To check if your battery cell is fine, try spinning it on a flat surface – if it spins, it might have gone bad. Obviously, this tip applies to user-removable batteries only.

Observe how fast your battery level drops

Not all phones have batteries that can be easily inspected by the user. If that's the case with your handset, you can diagnose the health of its cell by monitoring how fast its charge level drops. It is not supposed to drop by two or more percentage points at a time. (Most phones allow you to have their battery level displayed as a percentage in the status bar. If you can't find the option in its settings menu, try using a widget.) And if your battery goes from full to zero in a matter of hours even when you barely use your phone, its is probably a goner.

More battery diagnostics tips

iPhone users, here's something you might not know. Your iPhone keeps track of how many times its battery gets charged, and it also monitors the actual capacity of the cell inside it. However, this information is meant to be accessed only by Apple's support staff, hence you won't find it in your settings menu. Thankfully, there's a workaround. You just need to get iBackupBot – an all-in-one utility for managing iDevices, available on both Mac and PC (Download link). As soon as you connect your iPhone to a computer with iBackupBot running, the application will detect it and let you access detailed information about it. In iBackupBot, highlight your phone in the list of devices and choose "More Information". There you'll find your iPhone's charge cycle count, as well as the actual capacity of its battery. If the FullChargeCapacity figure is much lower than the one under DesignCapacity, then the battery may have to be replaced. (Keep in mind that a lithium-based battery usually loses about 20% of its capacity after 500 charge cycles.)

Android users, your phone also stores data about the health of its battery cell. To access it, try entering the code *#*#4636#*#* in your dialer –this should take you to a service menu where battery details are shown. If the code doesn't work, try Battery by MicroPinch (Download link). It is a simple battery monitoring tool where the health status of your battery is displayed, along with its voltage and temperature. 

Battery health tips

1. iBackupBot gives you detailed information about the health of your battery

How to tell if your smartphone's battery is healthy or bad

8:41 AM android, battery health, battery health check, battery issues, featured, how to, Iphone, iPhone battery check, spin test

WhatsApp on web disappoints some with no support for iPhone and many browsers

Why whatsapp for web not available for iPhone?

WhatsApp for web browsers was launched this week — but not for anyone with an iPhone or people using any browser apart from Chrome. But the limited features are likely a result of WhatsApp commitment to mobiles and privacy.

The Facebook-owned company announced this week that users could send messages from their PCs over the web. But while the feature is available for everyone on Android, BlackBerry, Windows or Nokia Phones, it wasn’t launched for iPhone and other browsers like Safari or Firefox.

Whatsapp blamed Apple for not being able to put the feature on iOS — citing “platform limitations”.

While other chat services like iMessage and Google Hangouts offer the option to sync accounts across phones and computers, they don’t have the same wide adoption as WhatsApp. iMessage is also limited to use on Apple devices, and Hangouts is much easier to use on Google’s phones, web clients and browsers.

As well as requiring Android and Chrome, WhatsApp on PC uses the network connection from the phone. That means that it can’t be used if your Android phone is out of signal, or run out of battery — two of the most helpful uses for being able to access the client on other devices.

But the limitations likely stem from two of WhatsApp’s key principles for the app: that it should always remain mobile first, and that communications should have end-to-end encryption so that they can’t be snooped on.

The way the web app works means that WhatsApp is able to make messages viewable on desktop without sacrificing its priority to keep things mobile. The web browser is essentially just a way of mirroring what’s happening on the app on your desktop.

“This means all of your messages still live on your phone,” as WhatsApp said in its statement — and it ensures that the web app stays as a useful utility rather than the beginning of any move to offer WhatsApp to non-mobile users.

The process is also likely to be a result of WhatsApp’s commitment to end-to-end encryption, though the company hasn’t said so. The slightly difficult way of linking phones to the web client, as well as the complications that exist when users have done so, are probably at least in part a result of WhatsApp’s commitment  not to read users’ messages and to stop other people from doing so.

WhatsApp on web disappoints some with no support for iPhone and many browsers

7:50 AM facebook, Iphone, whatsApp, WhatsApp desktop, whatsApp for web

3 Ways Steve Jobs Made Meetings Insanely Productive - And Often Terrifying

Productive meetings - Steve Jobs

Justin SullivanAmerican businesses lose an estimated $37 billion a year due to meeting mistakes.

Steve Jobs made sure that Apple wasn't one of those companies.

Here are three ways the iconic CEO made meetings super productive.

1. He kept meetings as small as possible.

In his book "Insanely Simple," longtime Jobs collaborator Ken Segall detailed what it was like to work with him.

In one story, Jobs was about to start a weekly meeting with Apple's ad agency.

Then Jobs spotted someone new.

"He stopped cold," Segall writes. "His eyes locked on to the one thing in the room that didn't look right. Pointing to Lorrie, he said, 'Who are you?'"

Calmly, she explained that she was asked to the meeting because she was a part of related marketing projects.

Jobs heard her, and then politely told her to get out.

"I don't think we need you in this meeting, Lorrie. Thanks," he said.

He was similarly ruthless with himself. When Barack Obama asked him to join a small gathering of tech moguls, Jobs declined - the President invited too many people for his taste.

2. He made sure someone was responsible for each item on the agenda.

In a 2011 feature investigating Apple's culture, Fortune reporter Adam Lashinsky detailed a few of the formal processes that Jobs used, which led Apple to become the world's most valuable company.

At the core of Job's mentality was the "accountability mindset" - meaning that processes were put in place so that everybody knew who was responsible for what.

As Lachinsky described:

"Internal Applespeak even has a name for it, the "DRI," or directly responsible individual. Often the DRI's name will appear on an agenda for a meeting, so everybody knows who is responsible. "Any effective meeting at Apple will have an action list," says a former employee. "Next to each action item will be the DRI." A common phrase heard around Apple when someone is trying to learn the right contact on a project: "Who's the DRI on that?"

The process works. Gloria Lin moved from the iPod team at Apple to leading the product team at Flipboard - and she brought DRIs with her.

They're hugely helpful in a startup situation.

"In a fast-growing company with tons of activity, important things get left on the table not because people are irresponsible but just because they're really busy," she wrote on Quora. "When you feel like something is your baby, then you really, really care about how it's doing."

3. He wouldn't let people hide behind PowerPoint.

Walter Isaacson, author of the "Steve Jobs" biography, said, "Jobs hated formal presentations, but he loved freewheeling face-to-face meetings."

Every Wednesday afternoon, he had an agenda-less meeting with his marketing and advertising team.

Slideshows were banned because Jobs wanted his team to debate passionately and think critically, all without leaning on technology.

"I hate the way people use slide presentations instead of thinking," Jobs told Isaacson. "People would confront a problem by creating a presentation. I wanted them to engage, to hash things out at the table, rather than show a bunch of slides. People who know what they're talking about don't need PowerPoint."

3 Ways Steve Jobs Made Meetings Insanely Productive - And Often Terrifying

1:40 PM Apple, Iphone, steve jobs

A dozen USB chargers in the lab: Apple is very good, but not quite the best

The World OF USB Chargers

When you buy a USB charger, how do you know if you're getting a safe, high-quality charger for your money? You can't tell from the outside if a charger provides silky-smooth power or if it is a dangerous charger that emits noisy power that cause touchscreen malfunctions[1] and could self-destruct. In this article, I carefully measure the performance of a dozen different chargers, rate their performance in multiple categories, and determine the winners and losers.

The above picture shows the twelve chargers I analyzed.[2] The charger in the upper-left is the cube-shaped Apple iPhone charger. Next is an oblong Samsung adapter and a cube Samsung adapter. The Apple iPad power adapter is substantially larger[3] than the iPhone charger but provides twice the power. The HP TouchPad power charger has an unusual cylindrical shape. Next is a counterfeit iPhone charger, which appears identical to the real thing but only costs a couple dollars. In the upper right, the Monoprice iPhone charger has a 30-pin dock connector, not USB. The colorful orange charger is a counterfeit of the Apple UK iPhone charger. Next is a counterfeit iPad charger that looks just like the real one. The Belkin power adapter is oval shaped. The KMS power supply provides four USB ports. The final charger is a Motorola Charger.

Summary of ratings

The chargers are rated from 1 to 5 energy bolts, with 5 bolts the best. The overall rating below is the average of the ratings in nine different categories, based on my measurements of efficiency, power stability, power quality, and power output. The quick summary is that phone manufacturers provide pretty good chargers, the aftermarket chargers are worse, and $2 counterfeit chargers are pretty much junk. Much to my surprise, the HP TouchPad charger (which isn't sold any more) turned out to have the best overall score. The counterfeit iPhone charger set a new low for bad quality, strikingly worse than the other two counterfeits.

	Model	Overall rating
Apple iPhone	Apple A1265
Samsung oblong	Samsung travel adapter ETA0U60JBE
Samsung cube	Samsung travel adapter ETA0U80JBE
Apple iPad	Apple 10W USB Power Adapter A1357
HP TouchPad	Hewlett Packard LPS AC/DC Adaptor P/N 157-10157-00
Counterfeit iPhone	Fake Apple A1265 "Designed by California"
Monoprice	Monoprice Switching Mode Power Supply MIPTC1A
Counterfeit UK	Fake Apple A1299
Counterfeit iPad	Fake Apple 10W USB Power Adapter A1357
Belkin	Belkin UTC001
KMS	KMS-AC09
Motorola	Motorola AC Power Supply DC4050US0301

Inside a charger

These chargers cram a lot of complex circuitry into a small package, as you can see from the iPhone charger below. (See my iPhone charger teardown for more details.) The small size makes it challenging to make an efficient, high-quality charger, while the commoditization of chargers and the demand for low prices pressure manufacturers to make the circuit as simple as possible and exclude expensive components, even if the power quality is worse. The result is a wide variation in the quality of the chargers, most of which is invisible to the user, who may believe "a charger is a charger".

Inside the iPhone charger

Internally a charger is an amazingly compact switching power supply that efficiently converts line AC into 5 volt DC output. The input AC is first converted to high-voltage DC. The DC is chopped up tens of thousands of times a second and fed into a tiny flyback transformer. The output of the transformer is converted to low-voltage DC, filtered, and provided as the 5 volt output through the USB port. A feedback mechanism regulates the chopping frequency to keep the output voltage stable. Name-brand chargers use a specialized control IC to run the charger, while cheap chargers cut corners by replacing the IC with a cheap, low-quality feedback circuit.[4]

A poor design can suffer several problems. If the output voltage is not filtered well, there will be noise and spikes due to the high-frequency switching. At extreme levels this could damage your phone, but the most common symptom is the touchscreen doesn't work while the charger is plugged in.[1] A second problem is the output voltage can be affected by the AC input, causing 120 Hz "ripple".[5] Third, the charger is supposed to provide a constant voltage. A poor design can cause the voltage to sag as the load increases. Your phone will take longer to charge if the charger doesn't provide enough power. Finally, USB chargers are not all interchangeable; the wrong type of charger may not work with your device.[6]

Counterfeits

Counterfeit chargers pose a safety hazard as well as a hazard to your phone. You can buy a charger that looks just like an Apple charger for about $2, but the charger is nothing like an Apple charger internally. The power is extremely bad quality (as I will show below). But more importantly, these chargers ignore safety standards. Since chargers have hundreds of volts internally, there's a big risk if a charger doesn't have proper insulation. You're putting your phone, and more importantly yourself, at risk if you use one of these chargers. I did a teardown of a counterfeit charger, which shows the differences in detail.

I've taken apart several counterfeit chargers and readers have sent me photos of others. Surprisingly, the counterfeit chargers I've examined all use different circuitry internally. If you get a counterfeit, it could be worse or better than what I've seen.

How do you tell if a charger is counterfeit? The fakes are very similar; it's hard for me to tell, even after studying many chargers. There's a video on how to distinguish real and fake chargers through subtle differences. You can also weigh the charger (if you have an accurate scale), and compare with the weights I give above. The easiest way to get a genuine Apple charger is fork over $29 to an Apple store. If you buy a $2 "Original Genuine Apple" charger on eBay shipped from China, I can guarantee it's counterfeit. On the other hand, I've succeeded in buying genuine used chargers from US resellers for a moderate price on eBay, but you're taking a chance.

The following picture shows a counterfeit charger that burned up. The safety issues with counterfeits are not just theoretical; when hundreds of volts short out, the results can be spectacular.

Photo by Anool Mahidharia. Used with permission

Indicated charger type

A device being charged can detect what type of charger is being used through specific voltages on the USB data pins.[6] Because of this, some devices only work with their own special chargers. For instance, an "incorrect" charger may be rejected by an iPhone 3GS or later with the message "Charging is not supported with this accessory".[7]

There are many different charger types, but only a few are used in the chargers I examined. A USB charger that follows the standard is known as a "dedicated USB charger". However, some manufacturers (such as Apple, Sony, and HP) don't follow the USB standard but implement their own proprietary charger types. Apple has separate charger types for 1 amp (iPhone) and 2 amp (iPad) chargers. HP has a special type for the HP TouchPad.

The point is that USB chargers are not interchangeable, and devices may not work if the charger type doesn't match what the device expects. The table below shows the type of charger, the current that the label claims the charger provides, the current it actually provides, and the charger type it indicates to the device.

The types of the counterfeit chargers are a mess, as they advertise one power level, actually supply a different power level, and have the charger type for a third level. For example, the counterfeit iPhone charger is advertised as supplying 1 amp, but has the 2A charger type, so an iPad will expect 2 amps but not obtain enough power. On the other hand, the counterfeit iPad charger claims to supply 2 amps, but really only supplies 1 amp and has a 1A type.

	Charger type	Label	Measured current	Weight
Apple iPhone	Apple 1A charger	5V 1A	1.79A	23.0g
Samsung oblong	dedicated USB charger	5V 0.7A	.80A	33.1g
Samsung cube	dedicated USB charger	5V 1A	1.17A	23.2g
Apple iPad	Apple 2A charger	5.1V 2.1A	2.3A	67.5g
HP TouchPad	HP TouchPad charger	5.3V 2.0A	2.4A	54.8g
Counterfeit iPhone	Apple 2A charger	5V 1A	.94A	18.8g
Monoprice	Apple dock	5V 1A	1.22A	67.8g
Counterfeit UK	dedicated USB charger	5V 1A	.57A	29.4g
Counterfeit iPad	Apple 1A charger	5.1V 2.1A	1.2A	43.4g
Belkin	Apple 1A charger	5V 1A	1.27A	43.0g
KMS	Apple 2A charger	5V 2.1A	3.4A	99.5g
Motorola	dedicated USB charger	5.1V .85A	.82A	38.6g

Efficiency

People often wonder how much power their charger is wasting while it's idle, and if they should unplug their charger when not in use. I measured this "vampire" power usage and found the chargers varied by more than a factor of 20 in their idle power usage. The Samsung oblong charger came in best, using just 19 mW; this was so low compared to the other chargers that I measured it again a different way to make sure I hadn't made an error. On the other extreme, the fake iPhone charger used 375 mW. The Apple iPhone charger performed surprisingly badly at 195 mW. If plugged in for a year, this would cost you about 21 cents in electricity, so it's probably not worth worrying about.[8] In the following table, I use the official charger Star Rating System (yes, there actually is such a thing).[9][10]

I also measured efficiency of the chargers under load.[11] One of the benefits of switching power supplies over simpler linear supplies is they are much more efficient at converting the input power to output. The chargers I measured all did pretty well, with 63% to 80% efficiency. The HP charger was the winner here.

	Vampire	milliwatts	Efficiency	Percent
Apple iPhone		195		74
Samsung oblong		19		76
Samsung cube		86		77
Apple iPad		62		78
HP TouchPad		91		80
Counterfeit iPhone		375		63
Monoprice		78		72
Counterfeit UK		103		63
Counterfeit iPad		95		66
Belkin		234		66
KMS		179		69
Motorola		59		75

The chargers up close

Apple iPhone and counterfeit

The above photo shows a real iPhone charger (left) and a counterfeit (right); the two chargers are almost identical, down to the green dot. If you look closely, the genuine one says "Designed by Apple in California", while the counterfeit has the puzzling text "Designed by California". The counterfeit also removed the "Apple Japan" text below the plug. I've seen another counterfeit that says "Designed by Abble" (not Apple). I assume the word "Apple" is removed for legal or trademark reasons, since the word "Apple" is often (but not always) missing from counterfeits.

Samsung oblong

I call this charger the Samsung oblong charger, to distinguish it from the Samsung cube charger.

Samsung cube

The Samsung cube charger is shaped very similarly to the Apple iPhone charger. Internally, however, it turns out to be entirely different.

Apple iPad and counterfeit

The photo above shows a real iPad charger (left) and a counterfeit (right). The counterfeit has almost identical text, but without "Designed by Apple in California. Assembled in China", "Listed" under UL, and the manufacturer "Foxlink". Inexplicably this sanitization left "TM and © 2010 Apple Inc".

The above photo shows a real iPad charger on the left and a fake iPad charger on the right, with the plug removed. The most visible difference is the real charger has a round metal grounding post, while the fake has plastic. (The US plug isn't grounded, but in other countries the lack of ground in the counterfeit could pose a safety hazard.)

HP TouchPad

 

The HP TouchPad charger has a very unusual cylindrical shape, which is striking if perhaps not practical. The charger twists apart, allowing the plug to be replaced for different countries. (It took me weeks to discover this feature.)

Monoprice

The Monoprice charger isn't a USB charger, but instead has a 30-pin iPhone dock connector attached. It is a relatively large charger.

Counterfeit UK

This charger is a counterfeit of the Apple UK iPhone charger. They've removed Apple from the text, but left Emerson Network Power, which I'm sure is not the actual manufacturer. The genuine Apple UK charger can be distinguished by a serial number inside the USB connector.

Belkin

The Belkin charger eschews the minimal design styling of most chargers, with a roughly oval cross section, curves and ribs, and a cover over the USB port.

KMS

The KMS charger is unusual in providing 4 USB ports. It also gives off a blue glow while in use. The plug can be removed and replaced for use in different countries, similar to the iPad and HP TouchPad chargers. I couldn't find any UL safety approval on this charger, but I did find a report of one catching fire.

Motorola

The Motorola charger has the lowest listed power output, 850mA. The back of it has a holographic sticker (like a credit card), which may ward off counterfeiters, even though it's unlikely for anyone to counterfeit this charger. I wonder though why Apple doesn't use holograms or other anti-counterfeiting techniques, given the large number of counterfeit Apple chargers being sold.

Delivery of advertised power

Each charger has an advertised power output, but some chargers produce considerably more and some produce much less. Your device will take longer to charge, if the charger can't put out enough power. This table shows each charger's ability to deliver the rated power, based on my measurements of maximum power. While most chargers meet or exceed the power rating, there are some exceptions.

The counterfeit chargers perform extremely poorly, putting out a fraction of the expected power. Charging your device with one of these chargers will be a slow, frustrating experience. In particular, the counterfeit UK charger only produces a third of the expected power. Although the label claims the charger works on 100-240 volts, it's clearly not designed to work on US power.

The iPad is a surprise, putting out less power than expected. Despite being nominally a 10 watt charger, the label says it provides 5.1V and 2.1A, which works out to 10.7 watts. However, the maximum power I measured is 10.1 watts (4.4 volts at 2.3 amps, as shown in the Power section below). Since the measured power is slightly less than advertised, it only gets four bolts.

	Rating	Label	Watts from label	Measured watts
Apple iPhone		5V 1A	5.0	6.0
Samsung oblong		5V 0.7A	3.5	4.0
Samsung cube		5V 1A	5.0	5.5
Apple iPad		5.1V 2.1A	10.7	10.1
HP TouchPad		5.3V 2.0A	10.6	11.4
Counterfeit iPhone		5V 1A	5.0	2.7
Monoprice		5V 1A	5.0	5.7
Counterfeit UK		5V 1A	5.0	1.7
Counterfeit iPad		5.1V 2.1A	10.7	5.9
Belkin		5V 1A	5.0	5.6
KMS		5V 2.1A	10.5	10.9
Motorola		5.1V .85A	4.3	4.3

Power quality

In this section, I measure the quality of the power produced by the different chargers. I analyze it for voltage spikes, high frequency noise, and line-frequency ripple. The following table summarizes the results in three categories. Spikes indicates extremely brief large voltage spikes in the output, while Noise indicates high-frequency noise in the output, and Ripple indicates low-frequency (120 Hz) fluctuations in the output.[12]

	Spikes	Noise	Ripple
Apple iPhone
Samsung oblong
Samsung cube
Apple iPad
HP TouchPad
Counterfeit iPhone
Monoprice
Counterfeit UK
Counterfeit iPad
Belkin
KMS
Motorola

The following oscilloscope traces show the output signal (yellow) and frequency spectrum (orange). The left images provide high-frequency information on the output voltage. The right images show the low-frequency information on the output voltage.[13]

The desired voltage graph is a flat, thin yellow line indicating totally smooth power. However, some factors mess this up. First, any ripple from the power line will show up as 5 sinusoidal peaks in the first (high-frequency) yellow line. High-frequency noise will widen the yellow line. Voltage spikes will appear as vertical spikes in the yellow line.

The plots also show the frequency spectrum in orange, from 0 at the left to 230 kHz at the right. The desired graph would have the orange spectrum near the bottom of the screen. Thus, the power quality exponentially gets worse as the orange line gets higher. The left (high frequency) spectrum generally shows noise at the switching frequency of the charger (and harmonics). The right (low frequency) spectrum typically shows spikes at multiples of 120 Hz, caused by ripple from the 60 Hz power.[5]

Apple iPhone

 

The ripple is clearly visible as the waves in the yellow trace on the left and as the spikes (at 120 Hz and 240 Hz) in the orange trace on the right.

The iPhone charger performs extremely well at filtering out spikes and noise, the best of the chargers I measured. Apart from the 120 Hz spikes, the noise spectrum (orange) is flat and very low. The power quality is so good, I checked the results several times to make sure I wasn't missing something.

Samsung oblong

 

The Samsung charger's output has a lot more noise than the iPhone charger. This is visible in the thickness and jaggedness of the yellow output curves. The orange frequency spectrum on the left shows large peaks at harmonics of the switching frequency. The 120 Hz spike on the right is a bit lower than the iPhone charger, so the ripple filtering is a bit better.

Samsung cube

 

The Samsung cube charger shows some noise in the output (yellow). The frequency spectrum shows wide peaks at multiples of the the switching frequency, about 90kHz. There's some ripple.

Apple iPad

 

The iPad charger almost eliminates the ripple; only a small blip is visible in the orange spectrum on the right. The noise level is low, although appreciably worse than the iPhone.

HP TouchPad

 

There's no ripple visible in the HP charger spectrum on the right. The overall noise level is good.

Counterfeit iPhone

 

The output from this counterfeit charger is a wall of noise. In order to fit the waveform in the display, I had to double the scale on the left and increase it by a factor of 5 on the right, so the yellow curve is actually much worse than it appears. On the left, note the huge ripple with massive high-frequency noise on top. This output is not something you want to feed into your phone.

Monoprice

 

The output from this charger is very noisy, as you can see from the thickness of the yellow line. Note that the frequency spectrum (left) has very tall but narrow spikes at harmonics of the 28kHz switching frequency, showing a lot of high-frequency noise. On the positive side, there is hardly any ripple.

Counterfeit UK

 

This charger has very bad output. The large degree of ripple is visible in the waveform (yellow, left) and the very large spikes in the spectrum (orange, right). The thickness of the yellow waveform shows the large amount of high-frequency noise, which is also visible in the very high peaks in the spectrum (orange, left).

Counterfeit iPad

 

This counterfeit charger has so much noise in the output that I had to double the scale on the left to get it to fit. Note the very large spikes in the output (yellow). The spectrum (orange, left) is much higher everywhere, indicating noise at all frequencies. Surprisingly, it has only a moderate amount of ripple; the manufacturer seems to have done at least one thing right.

Belkin

 

The Belkin charger does well at eliminating ripple, but has a lot of noise otherwise. The spectrum (orange, left) shows large peaks. The yellow output is wide, showing a lot of noise, combined with many large voltage spikes of about 1/3 volt.

KMS

 

The KMS charger has fairly good output, with a small peak in the spectrum (orange, left) at the switching frequency. It has no detectable ripple. However, it has many large voltage spikes in the output, over half a volt, as can be seen on the right.

Motorola

 

The Motorola charger has a lot of spikes in the output (yellow) . The spectrum (orange, left) shows high frequency noise at the switching frequencies. There's a moderate amount of ripple (yellow, left and orange, right).

Summary

The quality of the output power is radically different between chargers. The counterfeit chargers are uniformly bad, with hardly any effort at filtering the output. The other chargers vary in quality with the iPhone charger setting the standard for noise-free power, but surprisingly poor filtering of ripple. The power quality is a key factor that affects the performance of chargers; spikes and noise are known to interfere with touchscreens.[1]

Power curve

In this section I look at the voltage and current output by the charger as the load increases. The first rating is Voltage Sag, which is the undesired drop in output voltage as the load increases. The second rating is Current Sag, which shows how the current fluctuates as load increases. Finally,Regulation shows the overall stability of the output from the charger.

	Voltage sag	Current sag	Regulation
Apple iPhone
Samsung oblong
Samsung cube
Apple iPad
HP TouchPad
Counterfeit iPhone
Monoprice
Counterfeit UK
Counterfeit iPad
Belkin
KMS
Motorola

The graphs in this section need a bit of explanation, which is provided in the diagram below. The voltage/current load curve shows the performance of the charger under different loads. Each point on the curve shows the current (X axis) and voltage (Y axis) produced by the charger under a particular load condition. Follow the yellow curve clockwise from the upper left to the lower left to see the effect of increasing load. The upper left point of the curve shows the voltage produced by the charger when there is no load on the charger. As the load increases, the charger is supposed to keep a constant voltage and increase the current (i.e. horizontal line), until it reaches the maximum power (upper right). If the load continues increasing, the charger switches to a constant current mode, dropping the voltage while continuing to provide the maximum current (i.e. vertical line).[14] At the lower right, the charger has reached its shutdown point due to excessive load, and rapidly drops to no output in the lower left corner to avoid damage.

[16]

Apple iPhone

The output from the Apple iPhone charger is surprisingly non-constant under load. The charger starts off with 5.2 volts with no load, dropping to 4.6 volts as the load increases, resulting in the downwards slope of the top yellow line. As the load increases, the current keeps increasing, resulting in the slope of the right yellow line. Note however that the yellow line is relatively thin, so the regulation is pretty good at each point.

Note that because this charger has a high current output, this chart has a different current (horizontal) scale than most of the charts to fit the whole trace in the image. Stretch it horizontally to compare with other graphs.

Samsung oblong

For this charger, the voltage is approximately flat, except for a bump under no load (upper left) which is probably a measurement artifact. The vertical yellow line shows the current stays nearly constant as the load increases. The charger shows good voltage and current stability under changing load. The yellow line is a bit wider than the iPhone charger, showing a bit less regulation for a fixed load.

Samsung cube

The voltage curve sags slightly under load. The right hand curve shows the current stays stable, but the line is moderately wide, showing a bit of weakness in regulation.

Apple iPad

Similar to the iPhone charger, the iPad charger shows a lot of voltage sag. The voltage is about 5.1 V unloaded, dropping to 4.4 volts and 2.3 A (10.1 W) at the corner. Unlike the iPhone charger, the iPad charger has pretty good current stability. The regulation is solid, as shown by the narrowness of the yellow trace. Note the scale change due to the high current output.

I'm puzzled by the steep voltage sag on both the iPhone and iPad charger. Since the designers of the Apple charger went to a great deal of effort to build a high quality charger, I conclude they must not consider voltage sag worth worrying about. Or, more interestingly, maybe they built this sag as a feature for some reason. In any case, the chargers lose points on this.

HP TouchPad

The charger has some voltage sag, but the current (vertical) is nice and constant. The yellow line is relatively thin, showing good regulation. Note the scale change due to the high current output.

Counterfeit iPhone

This counterfeit charger shows extremely poor regulation, as shown by the very wide yellow line. It's hard to fit a voltage-current curve to this picture. The amount of power supplied by this charger seems almost random.

Monoprice

The Monoprice charger shows reasonably straight voltage and current lines showing good constant voltage and current outputs. The vertical line shows some width and noise, suggesting the regulation isn't totally stable.

Counterfeit UK

For this charger, the upper line doesn't get very far, showing that this charger doesn't output much current. My suspicion is that it was only tested with 240 volts so it performs poorly with 120 volts, even though the label says it takes 100 to 240 volts. The width of the yellow line shows very poor regulation.

Counterfeit iPad

The output of this counterfeit charger is so poorly regulated that it's hard to tell exactly what's happening with the voltage and current. It looks like the voltage is roughly constant underneath all the noise.

Belkin

The Belkin charger shows voltage sag as the current increases. In addition, the output is fairly noisy.

KMS

The KMS charger shows a lot of voltage sag as the load increases. In addition, the output is all over the place, showing very poor regulation, more like what I'd expect from a counterfeit charger. Note the scale change due to the high current output.

Motorola

The Motorola charger shows a bit of voltage sag, but good current stability. The regulation is good but not perfect, as shown by the width of the yellow line. (The gaps in the vertical line are just measurement artifacts.) Note that the maximum current output of this charger is fairly low (as advertised).

Conclusions

So what charger should you spend your hard-earned money on? First, make sure the charger will work with your phone - for instance, newer iPhones only work with certain chargers. Second, don't buy a counterfeit charger; the price is great, but it's not worth risking your expensive device or your safety. Beyond that, it's your decision on how much quality is worth versus price, and I hope the data here helps you make a decision.

P.S. How about some teardowns?

My previous iPhone charger and fake charger teardowns were surprisingly popular, but if you were hoping for teardowns on the full set of chargers, you'll need to wait for a future blog post. I haven't torn the chargers apart yet; if I need to take more measurements, I don't want to have just a pile of parts. But I do have some preview pictures to hold you over until my teardown article.

The above picture shows the internals of a counterfeit Apple iPhone cube charger. The two boards stack to form the compact cube shape. This charger blatantly tries to pass as a genuine Apple charger; unlike the "Designed by California" charger, this one exactly copies the "Designed by Apple in California" text from the real charger. Note the very simple circuitry[4] - there are no components on the other side of the board, no controller IC, and very little filtering. Also look at the terrible mounting of the transistor on the front right; clearly the build quality of this charger is poor. Finally, note the overall lack of insulation; this charger wouldn't meet UL safety standards and could easily short out. But on the plus side, this charger only cost a couple dollars.

The above $2 charger is notable for its low-profile design; it's about as thin as you can make a charger and still fit the power prongs and the USB port. The transformer is very short to fit into this charger. Like the previous charger, it uses a very simple circuit,[4] has little filtering, and almost no safety insulation.

 

Finally, the above pictures show the internals of the Samsung cube charger, which has circuit boards packed with tiny components and is much more advanced than the counterfeits (although slightly less complex than the Apple charger). Despite being very similar to the Apple charger on the outside, the Samsung charger uses an entirely different design and circuitry internally. One interesting design feature is the filter capacitors fit through the cut-out holes in the secondary circuit board, allowing the large filter capacitors to fit in the charger.

A dozen USB chargers in the lab: Apple is very good, but not quite the best

10:15 AM Apple, best USB charger, Iphone, Mobile charger, quality of charger, USB, USB charger comparison