Taming the usb jungle – technical article 1 unit electricity cost in andhra pradesh

Over the past decade, USB has become the connector of choice for the majority mobile and peripheral devices. Its ability to transfer data at high speeds as well as deliver a respectable amount of power for charging devices has ensured its popularity. While USB was designed to standardize connections between devices, not all manufacturers have gone along with this guiding principle. Whether seeking to add additional features to the interface cable or to perhaps insidiously ensnare end users to use their brand USB cable, the market has seen its fair share of proprietary USB cables over the past few years. We at CableWholesale share your pain in this and have decided to address this issue with October’s technical article. Without further ado. Proprietary USB

The bane of many consumers, proprietary USB cables have existed since USB was first used to connect and charge digital cameras and other portable devices. These USB cables with specialized connectors often force users to carry the cables with them wherever they go or else buy a spare for the home, office, car, etc. As the cable device end is unique to the vendor, users are forced to buy additional or replacement cables direct from the original manufacturer which more often than not, costs a premium price. Fortunately, many (but not all) manufacturers allow third-party companies to sell USB cables with their own style connectors for substantially cheaper price points. Why Do These Exist Anyway?

The need for proprietary cables has arisen from manufactures introducing more and more features into portable devices. As such, the standard four standard signal lines (two for power and two for data) are often not enough. With this in mind, most vendor/product specific USB cables have more than four pins with some, such as Apple’s iPod connector having a total of 30 pins. It should be noted that many of the connections are actually unused and serve as placeholders for future developments whether it be audio/visual streams, additional data lines or even more power. Furthermore, proprietary connectors often contain specialized locking or docking mechanisms built into the connector. Standardizing Mobile USB

Not only do proprietary USB cables take their toll on consumer’s pocketbooks through tying a specialized cable to a device with built-in obsolescence but they are also detrimental to the environment. In fact, mobile phones, chargers and other associated devices with proprietary connectors are responsible for tens of thousands on tons of e-waste globally per year. With this in mind, national pressure from the European Union and other countries have forced mobile device manufactures to streamline their USB connection selection over the past year.

Newer and slightly smaller than Mini-B USB, the Micro-B connector is designed for up to 10,000 insertion and removal cycles (doubling that of the Mini-B connector) due to moving the cleverly designed locking mechanism from the female port to the male connector-end. The Micro-B connector was recently adopted by the OMTP (Open Mobile Terminal Platform) as the common connection standard to support USB, audio, charging and more. Furthermore, industry heavyweights such as HTC, Motorola, Research In Motion, Samsung and Sony have similarly chosen to adopt the connector for all their smart phones.

With a the new Micro-B USB standard for mobile phones, consumers benefit by having a universal charging solution in addition to not having to replace the charger with each new phone purchase. Additionally, mobile phones can be directly charged off any USB port meaning the charger itself can be ditched for just the cable when one has access to a computer. The aforementioned environmental impact of this mobile connector standardization will be significant too, with many less wall warts finding there way into landfills than in past years.

The USB specification calls for a 5 V (±5%) supply which can be delivered at a number of different current settings called: "unit loads". For USB 2.0 a load unit is specified as 100 mA (0.5 W delivered) which has been raised to 150 mA (0.75 W delivered) for USB 3.0. USB 2.0 allows for a maximum 5 load units of power (500 mA, 2.5 W) while its successor allows for up to 6 load units (900 mA, 4.5 W) to be supplied to devices when requested.

A new revision to the USB specification implements an even higher power option for charging devices by shorting the two data lines with a 200 Ω resistance. Of course, the shorted data lines means that this method will provide power only with no data connectivity. However, this dedicated charging option allows for up to 9 W of power which more than enough for nearly any portable device.

All too often, consumers are mystified when after plugging their smart phone or other device into a computer via a USB cable to charge they discover their phone does not show it is charging or even in fact plugged in. Suprisingly, these devices are in fact charging although usually quite slowly. All USB chargers output 5 V at a specified current or wattage (These are derived via Ohm’s law: P = IV). The device will pull the current it requires from the charger. The more available current, the faster the charge.

There is no reason to worry about too much available current for a device. You will not damage or destroy a device due to too much current. This does not apply however to supplying the device with too much voltage though. Users need not worry about this as long as the port adheres to USB specifications. Electricity In An Analogy

Substituting moving water for flowing electricity, one can think of electric current as an amount of water flowing through a conduit. The voltage would be the equivalent to the water pressure. With this in mind, it does not matter whether you connect your device to a large or a smaller diameter conduit with the same water pressure as long as they both supply the required amount of water per time which would be the equivalent of electric power.

Not only has USB provided power and connectivity to billions of devices from mobile phones to printers but it has also spurred a whole industry devoted to USB powered novelties that vary from borderline useful to the truly ridiculous. Ajay Bhatt [Factoid: The inventor of USB at Intel in 1996] probably never saw this coming. The Fun USB Novelty Flash Drive

• A: No. The current draw is based only on what the device needs as long as the charging circuit has enough amps to cover it. For example, you will not damage your stereo by plugging it into a 20 A wall plug as opposed to a 15 A plug. The same applies here.