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Engineering Essentials
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175 results found for Engineering Essentials, displaying items 1 - 20
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June 25, 2009
Understanding Common-Mode And Differential-Mode Interference
When identifying and controlling electromagnetic interference (EMI), discussion of common-mode and differentialmode interference will likely dominate. Differential-mode interference is a signal that appears on two lines of a closed loop, but current flow is in opposite directions. This kind of interference essentially appears in series with the desired signal. The solution is an inductor in series with the high side (and/or low side) of the line and a...
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Louis E. Frenzel
June 25, 2009
EMI/EMC Regulations
Almost all governments have very specific rules and regulations related to the control of electromagnetic interference (EMI). Most spell out the parameters of what is allowed and methods of testing. In the U.S., EMI guidelines for commercial equipment are handled by the Federal Communications Commission (FCC). The Code of Federal Regulations (CFR) section 47 Parts 15, 18, and 68 contain relevant information that all engineers should be aware of when ...
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Louis E. Frenzel
June 25, 2009
The Dark Force Of Evil In Electronics: Electromagnetic Interference
Is there an electronic product or circuit that’s not susceptible to electromagnetic interference (EMI)? For that matter, are any devices EMI-free? Simply put, no. EEs wish it wasn’t the case, of course, but it’s a fact of life in electrical engineering— and it’s one of those things they typically don’t teach you in school. Most engineers find out about EMI on the job, where expunging it often takes more time than the original design itself. And don’t...
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Louis E. Frenzel
June 11, 2009
What Was That Noise?
“Noise” can have different meanings. It could be the common phenomenon of, say, a buzz in an audio system. Other times it may refer to something less acoustic, perhaps a limit on the precision of measurements. As an example of the way the latter has become more problematic for designers, consider the analog portion of one channel in an industrial control or automotive system. As IC and sensor supply voltages keep shrinking, that kind of noise has...
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Don Tuite
May 21, 2009
Bolster Overcurrent Protection With Chip Fuses
Chip fuses assume two roles in electronics: protecting end users from injury, and preventing damage to circuitry. These functions benefit both the owner and the vendor of a given piece of equipment. Over the last 10 years, market demand for electronic devices serving information technology, mobile, and consumer applications has risen dramatically. Alongside the rapidly increasing demand comes the greater risk of unexpected conditions in electronic...
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Ove Hach
May 7, 2009
Coax Connectors
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Louis E. Frenzel
, et al.
May 7, 2009
Coax Connectors
Just as important as the cable itself are the connectors that terminate coax cable. They’re a weak link since they also add to the signal attenuation and cause anomalies that can change the impedance slightly, causing reflections. Over the years, connectors have gotten better at minimizing attenuation and impedance mismatches. BNC, F, N, SMA, TNC, and UHF are the most commonly used coax connectors (see...
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Louis E. Frenzel
May 7, 2009
Industrial Automation Cables Meet Stringent Requirements
The Industrial Automation family of high-performance cables from Alpha Wire Co. promise industry-leading quality, reliability, and the performance to meet the rigorous requirements of major communication architectures, according to the company. The product line consists of five categories. The ControlNet components consist of a low-loss RG-6/U 75-O coaxial cable with a double braid/foil shielding for maximum signal integrity and run length. Available in one to...
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Staff
May 7, 2009
Coax Cables Eliminate Outer Jacket
The plenum DS-3 and DS-4 series of coax cables from Belden feature the company’s Banana Peel composite cable construction, reducing installation time and labor, according to the company. They’re designed for digital signal interconnect and cross-connect applications in telco central offices and data centers, as well as other large, complex installations with data/telecom plenum cable runs requiring DS-3/DS-4 signaling. The cables are available in two sizes, 26 AWG (735A...
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Staff
May 7, 2009
Coaxial Cable—Still The Best Way To Make An RF Connection
You know about coaxial cable (Fig. 1). We all use it in one form or another, and it seems simple enough. But while modern cable products are better than ever, there are some real subtitles in their selection and application. Connecting dc and low-frequency ac including audio is easy. You just run some wires from point A to point B. The biggest challenge may seem to lie in choosing the ...
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Louis E. Frenzel
April 23, 2009
Mechatronics Means Motors
Simple electric motors turn when you apply power. They have been used this way since their inception. Yet today, a microcontroller may be sitting between the motor and the switch, and motors can be found everywhere from white goods to hybrid vehicles. Electric motors are key to almost all robotic work as well, with a couple hydraulic motors included for good measure. Most electric motors utilize magnetics for motive power. But at the low end of the spectrum, it...
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William Wong
April 23, 2009
Motor Terms
Technically, the term electric motor includes all motors, but it’s typically used to refer to rotational motors. In linear electric motors, movement is linear instead of rotational. The stator is the fixed part of the motor. The rotor, which is the part of the motor that moves, typically rotates. The armature is the rotor coil. The commutator connects brushes...
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William Wong
April 9, 2009
For More Information
Information on the various IEEE standards groups can be found online. Though the site isn’t in a friendly format, it’s a good source of information. Published documents on works in process are hard to access and interpret, but it’s still worth a look. The Ethernet Alliance was started in 2005 to help foster the development of Ethernet and disseminate...
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Louis E. Frenzel
April 9, 2009
Ethernet: A History
Robert Metcalfe and his associates invented Ethernet in 1972 (see “Ethernet Prepositions”). The original Ethernet was a coax bus topology with a bit rate of 2.94 Mbits/s. During the next 10 years, it evolved into a 10-Mbit/s coax bus, and a frame format and protocol emerged. In 1983, the IEEE standardized this 10-Mbit/s version as 802.3 and designated it as 10Base5. It defined the physical-layer (PHY) and media-access-control (MAC) layers of the ...
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Louis E. Frenzel
April 9, 2009
Ethernet Prepositions
Ethernet, still going strong after 36 years, can be associated with these varied prepositions: up, into, across, over, and down. It’s going up in local-area-network (LAN) speed to 40 and 100 Gbits/s. Recall that we started Ethernet in 1973 at 2.94 Mbits/s. It’s going into the core of our long-haul networks, replacing Sonet at 40 Gbits/s today over long-haul dense wavelength-division multiplexing (DWDM). Terabit Ethernet is on ...
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Bob Metcalfe
April 9, 2009
Caught In The Ethernet
Upon entering its fourth decade, youâ??d think Ethernet would show signs of age, being pushed aside for newer, stateof- the-art networking technologies. Well, ummm, no. Rather, Ethernet has evolved in step with changing requirements and standards. In the beginning, it involved PC ports on a coax bus local-area network (LAN). Over time, the technology has morphed into many other forms of networking, from simple I/O ports on embedded controllers to...
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Louis E. Frenzel
March 26, 2009
LED Lighting And Light Pollution
LEDs are used in many different types of outdoor applications, from colorful decorative architectural lighting to high-power white-light applications like street lighting. Though using more light to create colorful decorative fixtures cranks up the usage numbers, the overall light pollution caused by lighting will decrease if LED lighting is employed in higher power, white-light applications. Why? It all comes down to the utilization factor. The overwhelming...
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Joe DeNicholas
March 26, 2009
LED Life Standards In And Out Of Luminaires
The U.S. Department of Energy (DoE) notes that LED luminaires and replacement lamps available today often claim long life, usually 50,000 hours, based solely on the estimated lumen depreciation of the LED. But the DoE also says that life claims ought to account for the whole system. The lifetimes of incandescent, fluorescent, and high-intensity discharge lamps are generally estimated through industry standards. Typically, a large, statistically significant sample of lamps is ...
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Don Tuite
March 26, 2009
High-Brightness White LEDs Light The Way To Greener Illumination
LED illumination for building interiors and outdoor public spaces continues to gain serious traction, opening up new opportunities for electronic designers. For example, National Semiconductor’s LM3445 and NXP’s SSL2101 monolithic controllers for high-brightness (HB) white LED (WLED) building lighting accommodate legacy triac dimmers while providing wide-range dimming and power factor correction (PFC). Meanwhile, Texas Instruments and Microchip...
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Don Tuite
March 12, 2009
Rechargeable-Battery Power Management Demands Multiple ICs
Virtually all battery-based powermanagement designs depend on the associated battery, so design starts by picking the specific battery type. The battery may be the non-rechargeable primary type or the rechargeable secondary type. (For more, see “Batteries 101: From Nickel To Lithium And Beyond” at www.electronicdesign.com, ...
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Sam Davis
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