Fiddly cables, incompatible plugs and sockets, and the many adaptors needed to fit them all together used to be the travellers’ bane. But the USB (Universal Serial Bus) has simplified their life. Most phones and other small gadgets can charge from a simple USB cable plugged into a computer or an adaptor. Some 10 billion of them are already in use. Hotel rooms, aircraft seats, cars and new buildings increasingly come with USB sockets as a standard electrical fitting.
Now a much bigger change is looming. From 2014, a USB cable will be able to provide power to bigger electronic devices. In the long term this could change the way homes and offices use electricity, cutting costs and improving efficiency.
The man who invented the USB, Ajay Bhatt of Intel, a chipmaker, barely thought about power. His main aim was to cut the clutter and time-wasting involved in plugging things into a computer. The keyboard, mouse, speakers and so forth all required different cables, and often drivers (special bits of software) as well. The USB connection’s chief role was to help computers and devices negotiate and communicate.
Mr Bhatt did not think he was creating a new charging system. Indeed, the trickle of electricity (up to ten watts on the existing standard) is still barely enough for devices such as an iPad. Yet USB charging is now the default for phones, e-readers and other small gadgets. Some mobile-phone manufacturers are already shipping their products without a power adaptor. Ingenious inventors have eked out the slender USB power supply to run fans, tiny fridges and toy rocket-launchers.
The big change next year will be a new USB PD (Power Delivery) standard, which brings much more flexibility and ten times as much oomph: up to 100 watts. In his London office Simon Daniel, founder of Moixa, a technology company, charges his laptop from a prototype souped-up USB socket. The office lighting, which uses low-voltage LED (light-emitting diode) lamps, runs from the same circuit. So do the monitors, printers and (with some fiddling) desktops. Mains power is only for power-thirsty microwaves, kettles and the like.
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