CIRCUITS and DEVICES
Are You Ready for Virtual Money?
If you are among the folks who believe that the USA should go back on the gold standard or if you
believe that money has value only if "backed"
(whatever that means) by a fiscally responsible
national government (assuming you can find one), this
concept will not sit well. If you're a bold
speculator/anarchist/dealer in contraband, online
gambler, or a resident of a country whose currency is
swirling down the toilet, you might be interested in
the Bitcoin — a digital crypto-currency that exists
outside of the world of central banks and
governments.
Created in 2009 by someone who goes by the
pseudonym of Satoshi Nakamoto, it is basically a
totally anonymous peer-to-peer payment system.
Bitcoin transactions are secured by military-grade
cryptography, are recognized internationally, and cost
relatively little. Like other currencies, each Bitcoin is
subdivided — in this case, down to eight decimal
places — which gives you 100 million "satoshis"
per coin. Bitcoins are created by the Bitcoin
Project ( bitcoin.org), but they are distributed
through exchanges.
Although it seems like something of a Ponzi
scheme (and it could work out that way in the end),
the monetarist economists among us will at least like
the fact that the existing number of Bitcoins in virtual
existence has a strict, self-imposed limit of 21 million,
and it won't reach that number until 2140. This means
that the currency will not be subject to Federal
Reserve-style inflation. The value of a Bitcoin is based
only on its perceived value in the market, so one
might expect it to fluctuate wildly. And one would be
correct. On April 10, for example, it opened at $230,
shot up to $266, then dropped to $105 and closed at
$165. Right now, you can buy one for $77. As an
investment, this is not for the faint of heart.
In any event, if you want to get involved, you first
need to set up a virtual wallet to hold your funds and
trade some dollars for Bitcoins. There are several
places to do that, but Mt. Gox ( mtgox.com) handles
about 80% of the world's exchanges. You're then
ready to start buying things, or you can just hold onto
your Bitcoins in the hope that they will become more
valuable. ▲
10 September 2013
COMPUTERS and NETWORKING continued
Better Smartphone Pix
One of the limiting factors in taking high-quality photos with your smartphone is the flash driver which
typically puts out only about 2A to drive the LED.
However, ams AG ( www.ams.com) has figured out a way
to boost that to 8A by incorporating a Murata
supercapacitor called an electric double layer capacitor
(EDLC).
Driving two LEDs in series with power from the
supercap — as well as the phone's battery output — the
output is boosted to better than 9V to match the forward
voltage of the LEDs. This allows faster shutter speeds,
allowing sharper images and a less blurry capture of fast-moving objects. No details were provided about what
smartphones will be incorporating the AS3630 drivers, but
price shouldn't be an obstacle. The devices are priced at
just $2.19 in quantities of 1,000. ▲
■ Block diagram of the ams AS3630 photo flash driver.
