Sizing Up Circuit Protection for LED Strings

By Teddy To, Littelfuse, Inc., Chicago, IL As light-emitting diodes (LEDs) find their way into more outdoor applications, they are at higher risk for electrostatic discharge (ESD) and other electrical transients. High-brightness (HB) LEDs — those with sapphire or silicone carbide (SiC) substrates and in the future aluminum nitride (AlN) and gallium nitride (GaN) substrates — are especially susceptible, and when the first LED in a string fails, the whole string goes dark. Few engineers know all the considerations of specifying circuit protection for LED strings. For example, a recent category of devices, called open LED protectors, are now available, and are not well understood. This article will discuss when to apply them, how to size them, and how to save cost by protecting multiple strings with a single device.

Posted in: Articles, Lighting, Test & Inspection


Taking the Heat: Silicone’s Unique Properties Help Create the Next Generation of LED Lighting

By Kaz Maruyama and Hugo da Silva, Dow Corning Corporation, Midland, MI As global energy demand rises, the significant energy-saving potential of light-emitting diode (LED) lighting remains a top consideration for lighting manufacturers as well as designers, architects, and consultants looking to offer clients more sustainable options. LED lighting uses one-tenth the power of standard incandescent lighting and lasts 25 times longer — it even has the long-term potential to produce more light, with less cost, than compact fluorescent lamps, or CFLs. In fact, LED lighting may soon replace most lighting in homes, offices, public spaces, and in many other applications.

Posted in: Articles, Lighting, Materials & Packaging


YouTube and NASA Want Student Experiments

NASA has partnered with Space Adventures to support the YouTube Space Lab competition that invites students to envision and design their own experiment with the ultimate prize -- flying it on the International Space Station.The contest opened on October 11, and will continue to accept submissions in the form of a two-minute video through December 7. Students age 14 to 18 can become researchers by proposing up to three separate original entries on the official YouTube Space Lab contest Web site. Participants can enter as individuals or in teams of up to three people. Entries must include an experiment question, hypothesis, method, and expected results.

Posted in: Articles, Manufacturing & Prototyping


Meet Our Readers: Ken Polcak, Noise Abatement Design & Analysis Team Leader

In this NASA Tech Briefs "Meet Our Readers" Q&A, we feature Ken Polcak, Noise Abatement Design & Analysis Team Leader for the Maryland State Highway Administration.Polcak is a civil engineer by training and acoustical/noise control engineer by practice. He deals with transportation noise analysis and mitigation. Polcak's experience centers on the acoustical design of noise barriers, computer prediction and modeling of propagation, field testing and research, and impact assessment.

Posted in: Articles, Sensors, Transportation


Breakthrough in Preventing Food-borne Illnesses Wins $20,000 Grand Prize in Global Design Contest

"Create the Future" Design Contest sponsored by PTC®, COMSOL, and Tech Briefs Media attracts over 900 innovative product ideas from engineers and students in 50 countries.New York, NY – A new invention could protect millions from contracting food-borne illnesses. The αScreen is a portable, rapid pathogen screener that could allow screening of up to 100% of food produced in processing plants, before it is delivered to the consumer. αScreen is highly accurate, can detect as low as a single bacteria, and is approximately 50 times less expensive than the established, currently used detection methods.Monika Weber of New Haven, CT, a graduate student at Yale University, is the team leader on this design project. She and a select team of students at Yale University’s School of Engineering and Applied Science are responsible for the advancement of the design. Monika spent two years working on preliminary projects in bio-detection before the design for the αScreen was finalized.

Posted in: Articles, Medical


Specialized Thin Film Coatings for Unmanned Aircraft Systems

Unmanned aircraft systems (UAS) and their applications are experiencing rapid growth, especially in the area of remote sensing. Advances in propulsion; airframe materials; communications, command and control (C3) systems; cameras and detectors; and image processing are combining to continuously improve UAS capabilities. Most optical systems used in unmanned aircraft systems function over the visible (VIS) and near-infrared (NIR) wavelength ranges. Increasing in importance is multispectral or hyperspectral imaging which can combine information from VIS, NIR, mid-wave infrared (MWIR), and long-wave infrared (LWIR) wavelength regions to provide enhanced detection, such as chemical, vehicular, or terrain identification capabilities not available by the use of imaging alone. This article will cover some of the basics of optical thin film coatings as applied to electro-optical systems commonly used in unmanned systems (Figure 1).

Posted in: Articles, Features, ptb catchall, Photonics


Driving Growth and Innovation With Sustainable Design

Sustainable design — a dedicated effort to create products in a manner that minimizes their negative impact on the environment, making them more economically viable, socially acceptable, and ecologically tenable — is often misunderstood. In the past, many manufacturers viewed efforts to become more environmentally friendly as expenses rather than opportunities.

Posted in: Articles, Green Design & Manufacturing


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