CIRCUITS AND DEVICES
OSCILLATORS OFFER EMI REDUCTION
Major sources of electromagnetic interference (EMI) in electronic circuits include such frequency sources
as phase lock loop (PLL) synthesizers, quartz oscillators,
and other clock signal generators. This is often
ameliorated by using filters, shielded enclosures, and
complex grounding schemes. But employing a spread
spectrum crystal clock oscillator — in which the output
frequency is modulated — can reduce EMI at the source
which can result in simplified regulatory testing and
reduced system costs.
Two such devices — the SSOC5 and SSOC7 — were
recently introduced by Precision Devices, Inc.
www.pdixtal.com), intended for applications including
office equipment, computer systems,
telecommunications, set top boxes, and embedded
reduce EMI by as
much as 15 dBc as
compared to fixed
THE OTHER LIGHTING ALTERNATIVE
There has been considerable controversy over tungsten vs. compact fluorescent (CFL) bulbs of late, but relatively little discussion about the other alternative: LED lighting. LEDs have become increasingly viable over the last few years and,
in fact, can provide both energy efficiency and high quality light —
particularly in recessed lighting installations where omnidirectional
emission isn't so important.
An example is the new 1,000 lumen LMR4 module from Cree,
Inc. The unit delivers 66 lumens per watt which they claim is 42
percent better than a 26 W CFL. The LMR4 is said to be the only
2,700K LED module that delivers more than 90 CRI, making it a
good replacement for 100W incandescent bulbs in downlight
applications. They are also available in color temperatures of 3,000,
3,500, and 4,000K. All are designed to last 35,000 hr and are
dimmable to five percent.
More info and sample evaluation kits are available at
www.cree.com/modules. The company also markets blue and green
LED chips, high brightness LEDs, lighting-class power LEDs, power-switching devices, and RF/wireless devices. ▲
■ Cree's LMR4 LED lighting module — a viable
replacement for 100W incandescents.
JUST FOR FUN
It's always nice to run into a gadget that has no practical function but is super cool, anyway. Such is the Firewinder LED Windlight, devised by the VP of Evil
Schemes and Nefarious Plans (his real title, by the way) at ThinkGeek
www.thinkgeek.com). The Firewinder is a 100 percent wind-powered outdoor
light, built from recyclable materials and designed to resist weather extremes.
Drawing on wind power collected by a helical wing, it creates a spiral of light
for your patio or front yard. It takes only a 4 MPH breeze to set the Firewinder
spinning and power up the 14 ultra-bright LEDs, but it glows brighter if the
weather gets more tempestuous. It comes with "high performance fixtures" for
sturdy installation on a post or wall, and features a quick-release system so you
can tuck it inside if you spot a tornado. It will
run you $59.99, but what the heck. NV
■ The Firewinder LED Windlight
visualizes wind energy.