Science and Engineering Forum

How many times every day do you hear recorded music on the  radios  on  TV , in stores, in  elevators —even in the street? You'd never hear music at all if it weren't for  loudspeakers : electric sound-making machines. Most of the music we hear around us is played back with big loudspeakers attached to stereos or tiny earbud  headphones .  Radios ,  televisions ,  computers ,  cellular phones , intercoms, and talking toys are just some of the electric gadgets that make sounds with loudspeakers. But what exactly are loudspeakers and how do they work? Photo: These neat little Sony bookshelf speakers have a built-in  amplifier  and a long jack lead, so you can plug them into a  CD player ,  MP3 player ,  computer , or anything else with a standard headphone socket. They pack quite a punch for something so tiny because they have a reasonably high sensitivity, which is explained below. How loudspeakers turn ele...

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Whether because of the war on bezels or because it’s simply more ergonomic, it seems like more and more smartphone manufacturers are moving fingerprint sensors to back of their phones. Most flagships have them. The  HTC U11+  recently opted for a rear fingerprint scanner for the first time, and the newly announced  Galaxy S9   has one as well (in the right place this time, too). But Vivo is going in a different direction. Only a month after unveiling the  X20 Plus UD  at CES 2018, which featured a fingerprint scanner underneath the display, Vivo is now showing off the APEX FullView Concept Phone, which takes the idea even further. Where the X20 Plus UD had a glowing fingerprint on the display with a sensor embedded underneath, this new concept phone makes the entire bottom half of the screen capable of reading your fingerprint. Instead of a small light shining where the sensor was, this new concept phone shines a large block of light...

D igital cameras give a whole new meaning to the idea of painting by numbers. Unlike old-style  film cameras , they capture and record images of the world around us using digital technology. In other words, they store photographs not as patterns of darkness and light but as long strings of numbers. This has many advantages: it gives us instant photographs, allows us to edit our pictures, and makes it easier for us to share photographs using  cell phones  (mobile phones), e-mail, and  web sites . Photo: A typical low-cost digital camera. The circle is the lens; the rectangle above it is a  xenon flash lamp . You can see what this camera looks like inside in the photo lower down this page. How ordinary film cameras work Photo: An old-style film camera from the late 1980s. The film loads in a spool on the right and winds across to another spool on the left, passing in front of the lens on the way. When you take a photo, the shutter lets  light ...

The following is excerpted from Chapter 3: Radio Basics for UHF RFID from the Book,  The RF in RFID: Passive UHF RFID in Practice  by Daniel M. Dobkin. Order a copy of  The RF in RFID: Passive UHF RFID in Practice  before December 31, 2007 to receive an additional 20% off! Visit  www.newnespress.com  or call 1-800-545-2522 and use code 91090. While this book excerpt from The RF in RFID:Passive UHF RFID in Practice, focuses on RFID applications, it is an excellent primer for RF basics.  Part 1  covers electromagnetic waves, signal voltage, and power.  Part 2  covers modulation and multiplexing. Part 4  reveals how to determine the link budget. Part 5  focuses on the effect of antenna gain on range. Part 6  covers antenna polarization. Part 7  covers antenna propagation. This Part covers backscatter radio links and introduces link budgets. Backscatter Radio Links Passive and semipassive RFID tags do not use a ra...

Every entrepreneur knows that  productivity  is one of the key ingredients for successful product development. One of the two key processes in Robert’s Rules of Innovation is the  NEW PRODUCT DEVELOPMENT PROCESS . A formalized, NPD process – also referred to and best practice: the Stage Gate® Process – is a must, from simple to sophisticated. The New Product Development process is often referred to as The Stage-Gate innovation process, developed by Dr. Robert G. Cooper as a result of comprehensive research on reasons why products succeed and why they fail. When teams collaborate in developing new innovations, having the following eight ingredients mixed into your team’s new product developmental repertoire will ensure that it’s overall marketability will happen relatively quick, and accurately – making everyone productive across the board. Step 1:  Generating Utilizing basic internal and external SWOT analyses, as well as current marketing tr...