January 08, 2019 Volume 15 Issue 01

Electrical/Electronic News & Products

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New Hot Tap Digital Flowmeters simplify installation

EXAIR's new Hot Tap Digital Flowmeters allow installation when compressed air piping is under pressure. By eliminating the need to isolate and remove pressure from the pipe, these compressed air flowmeters reduce installation time while maintaining safety. Hot Tap Digital Flowmeters incorporate two valves that the measuring probes pass through. A sound muffler that also collects chips from the drilling process eliminates installation debris from entering the airstream and minimizes noise exposure. Measuring compressed air is the first step toward identifying high compressed air use areas, compressed air leaks and optimizing air use.
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Just out! Most powerful Raspberry Pi ever

The new Raspberry Pi 4 Model B Computer is the most powerful Raspberry Pi model ever. It offers significant enhancements in processor speed, multimedia performance, memory, and connectivity that will make it attractive to general desktop computer users, hobbyist and makers, and professional developers working with compute-intensive embedded applications such as computer vision and Artificial Intelligence (AI). Available in 1-GB, 2-GB, and 4-GB models.
Read the full article.


Angle sensors retain position -- even without power!

The RSB 3600 Series of absolute single-turn angle sensors from Novotechnik U.S. are EGMR (enhanced giant magnetic resistance) devices that retain their angular position even when power is removed. The sensors retain that angle information for years without power, so there is no need for batteries. Operating speed is up to 12,000 RPM. These non-contact sensors feature a galvanized steel housing and stainless steel shaft with up to 100 N working shaft load for the HD version. They are sealed up to IP 69K, depending on version. They count to 16 turns, angular position 0 to 360 deg. MTTF of more than 105 years.
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Overvoltage protection for motors, white goods, more

The RV from Stackpole is a radial leaded metal oxide varistor available in a wide range of disk sizes (5 mm to 20 mm) and working voltages (from 14 VDC to 1,465 VDC) designed for general-purpose overvoltage protection. Peak current ratings up to 18,000 amps. Applications include low-voltage board-level circuitry, data and voice communications, network equipment, distribution panels, AC line protection for white goods, entertainment electronics, lighting ballasts, power supplies, electric motors and motor controls, and surge protection devices.
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Extreme-force electric actuator for press and punch

Tolomatic's RSX extreme force electric actuator family has been expanded -- this time with more options capable of replacing hydraulic cylinders. The new RSX096P Press Model is designed for pressing, punching, clinching, joining, and other applications requiring extreme force. This hydraulic-class actuator is capable of forces up to 40,000 lbf (178 kN). It features Tolomatic planetary roller screw technology for long life and consistent performance.
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New optical joysticks for medical and military

CTI Electronics (an affiliate of Electro Switch Corp.) has launched a new line of optical joystick motion controllers and mouse pointing devices. Made in the USA, LightStick Series controllers exceed medical and military performance standards for electromagnetic and RF disturbance in applications to 200 V/m -- without additional shielding. The LightStick's patented noncontact optical sensor technology ensures highly repeatable operator feedback for the life of the controller -- up to 10 million cycles and a MTBF greater than 10 years of operation.
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UV-protected and waterproof panel mount indicators

Visual Communi-cations Company (VCC) recently announced the addition of its new PML50 Series Waterproof LED panel mount indicator (PMI). The new semi-dome indicator offers the same great features as the other PMIs in the PML50 family, with the added bonus of UV protection. This PMI has a white diffused lens for optimal side distance viewing and UV-resistant lens for superior performance in outdoor harsh environments -- and it will not discolor or fade. It achieves full brightness in microseconds, even in daylight viewing conditions. Ideal for a range of industries where outdoor status indication is crucial, including maritime, oil, gas, transportation, and industrial.
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Dual-mode automotive image sensor

The OV2312 automotive image sensor from OmniVision Technologies enables multiple functions in one camera, reducing the total system cost, space, and power budget for driver state monitoring (DSM) and viewing applications like video conferencing. The ability to capture both RGB and IR images with one global shutter (GS) sensor reduces the number of cameras needed. It provides dual-mode cameras with motion-artifact-free images at high resolutions of 1,600 x 1,300 at 60 fps and 1,280 x 720 at 90 fps. Because this is the smallest 2MP GS sensor in its class, cameras can be placed out of sight from drivers and passengers.
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High-deflection thermal gap filler

Laird Performance Materials has developed Tflex HD80000, a high-deflection thermal gap filler combining 6 W/mK thermal conductivity with superior pressure versus deflection characteristics. The combination allows minimal stress on sensitive components while also yielding low thermal resistance. As a result, less mechanical and thermal stresses are experienced in devices designed for telecom, information technology, consumer, industrial, aerospace, and military markets. Gap fillers bridge the interface between hot components and a chassis or heat sink assembly to increase the overall heat transfer from the system.
Learn more.


Why convert hydraulics to electric high-force linear actuators?

Got a high-force linear motion application? If you do, chances are the first product solution to come to mind is hydraulic cylinders. They're relatively inexpensive (if you already have a hydraulic power unit in place), compact (if the HPU is somewhere else), and power-dense. But what about the disadvantages -- leaks, operation and maintenance costs, and more? It's possible to convert an application from hydraulic to electric linear motion easily, and Tolomatic even gives you step-by-step instructions.
Read the Tolomatic blog. Really useful!


Cool heat-sensitive CMOS sensors with thermoelectric modules

Laird Thermal Systems has expanded its Peltier thermoelectric module product family with the HiTemp ET Series, designed to protect critical electronic devices like CMOS sensors in high-temp applications. Recent advances in CMOS sensor tech have made these sensors practical and effective for use in a wide range of imaging applications found in autonomous systems, machine vision and learning, high-end scientific cameras, and more. HiTemp ET Series thermoelectric modules deliver spot cooling capacity of more than 300 W to ensure optimum CMOS sensor performance. Fifty-three models offer a variety of heat-pumping capacities, geometric form factors, and input voltages.
Learn more.


Mini LVDTs offer position feedback for UAVs

Unmanned drones require a variety of sensors to monitor different critical measurements to control flight and maintain aircraft stability. Miniature Linear Position Sensors from NewTek Sensor Solutions provide reliable position feedback for monitoring the fin/rudder position and rotor angle of unmanned aerial vehicles (UAVs) with quick response times, so drones can make adjustments to accurately control flight.
Learn more.


Cobham introduces spacecraft, satellite electronics

Cobham Advanced Electronic Solutions, a leading provider of electronics technology and services for space and other high-reliability applications, recently released the new LeanREL product family designed to meet the needs of small satellite and non-traditional spacecraft manufacturers. The LeanREL product family, comprised of microprocessors, microcontrollers, as well as memory and interface integrated circuits (ICs), leverages Cobham's 30+ years of radiation-hardened, QML-level reliability, and innovative space systems design expertise and offers an unmatched combination of user benefits.
Find out more.


Touch panels require 50 percent less input force

Fujitsu Components America has just released a series of customizable, flush-surface, resistive touch panels with less than half the input force of conventional resistive panels, nearly identical to that of projected capacitive panels. The new series (FID-1300 4-wire and FID-1520 5-wire) offers OEMs a cost-efficient alternative to projected capacitive touch panels with a comparable user experience, while maintaining resistive technology's reliable input capability and unlimited choice of input sources. Target applications include industrial automation and HMI machine control, medical equipment, and vehicle navigation systems.
Learn more.


Automatic vision system with max throughput

The new AV450 Automatic Vision System from L.S. Starrett Company is a versatile, accurate, fast, and American-made 3-axis vision system that allows users to achieve high throughput in their inspection process cost effectively. This heavy-duty CNC video-based measurement system is ideal for both repetitive, larger part-run applications and routine quality assurance in inspection labs, manufacturing, assembly, and research facilities.
Learn more.


New way to do solar power: Researchers boost efficiency and stability of optical rectennas

Georgia Tech researchers have developed a new higher efficiency rectenna design. Here, the device's ability to convert blue light to electricity is tested. [Credit: Christopher Moore, Georgia Tech]

 

 

By John Toon, Georgia Tech

The research team that announced the first optical rectenna in 2015 is now reporting a two-fold efficiency improvement in the devices -- and a switch to air-stable diode materials. The improvements could allow the rectennas, which convert electromagnetic fields at optical frequencies directly to electrical current, to operate low-power devices such as temperature sensors.

Ultimately, the researchers believe their device design, which is a combination of a carbon nanotube antenna and diode rectifier, could compete with conventional photovoltaic technologies for producing electricity from sunlight and other sources. The same technology used in the rectennas could also directly convert thermal energy to electricity.

"This work takes a significant leap forward in both fundamental understanding and practical efficiency for the optical rectenna device," said Baratunde Cola, an associate professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology. "It opens up this technology to many more researchers who can join forces with us to advance the optical rectenna technology to help power a range of applications, including space flight."

The research was reported January 26 in the journal Advanced Electronic Materials. The work has been supported by the U.S. Army Research Office under the Young Investigator Program, and by the National Science Foundation.

Optical rectennas operate by coupling the light's electromagnetic field to an antenna, in this case an array of multiwall carbon nanotubes whose ends have been opened. The electromagnetic field creates an oscillation in the antenna, producing an alternating flow of electrons. When the electron flow reaches a peak at one end of the antenna, the diode closes, trapping the electrons, then re-opens to capture the next oscillation, creating a current flow.

Optical rectenna schematic: This schematic shows the components of the optical rectenna developed at the Georgia Institute of Technology. [Credit: Thomas Bougher, Georgia Tech]

 

 

The switching must occur at terahertz frequencies to match the light. The junction between the antenna and diode must provide minimal resistance to electrons flowing through it while open, yet prevent leakage while closed.

"The name of the game is maximizing the number of electrons that get excited in the carbon nanotube, and then having a switch that is fast enough to capture them at their peak," Cola explained. "The faster you switch, the more electrons you can catch on one side of the oscillation."

To provide a low work function (ease of electron flow), the researchers initially used calcium as the metal in their oxide insulator/metal diode junction. But calcium breaks down rapidly in air, meaning the device had to be encapsulated during operation -- and fabricated in a glovebox. That made the optical rectenna both impractical for most applications and difficult to fabricate.

So Cola, NSF Graduate Research Fellow Erik Anderson, and Research Engineer Thomas Bougher replaced the calcium with aluminum and tried a variety of oxide materials on the carbon nanotubes before settling on a bilayer material composed of alumina (Al2O3) and hafnium dioxide (HfO2). The combination coating for the carbon nanotube junction, created through an atomic deposition process, provides the quantum mechanical electron tunneling properties required by engineering the oxide electronic properties instead of the metals, which allows air stable metals with higher work functions than calcium to be used.

Rectennas fabricated with the new combination have remained functional for as long as a year. Other metal oxides could also be used, Cola said.

The researchers also engineered the slope of the hill down which the electrons fall in the tunneling process. That also helped increase the efficiency, and allows the use of a variety of oxide materials. The new design also increased the asymmetry of the diodes, which boosted efficiency.

"By working with the oxide electron affinity, we were able to increase the asymmetry by more than ten-fold, making this diode design more attractive," said Cola. "That's really where we got the efficiency gain in this new version of the device."

Optical rectennas could theoretically compete with photovoltaic materials for converting sunlight into electricity. PV materials operate using a different principle, in which photons knock electrons from the atoms of certain materials. The electrons are collected into electrical current.

In September 2015 in the journal Nature Nanotechnology, Cola and Bougher reported the first optical rectenna -- a device that had been proposed theoretically for more than 40 years, but never demonstrated.

The early version reported in the journal produced power at microvolt levels. The rectenna now produces power in the millivolt range, and conversion efficiency has gone from 10-5 to 10-3 -- still very low, but a significant gain.

"Though there still is room for significant improvement, this puts the voltage in the range where you could see optical rectennas operating low-power sensors," Cola said. "There are a lot of device geometry steps you could take to do something useful with the optical rectenna today in voltage-driven devices that don't require significant current."

Cola believes the rectennas could be useful for powering internet of things devices, especially if they can be used to produce electricity from scavenged thermal energy. For converting heat to electricity, the principle is the same as for light-capturing oscillations in a field with the broadband carbon nanotube antenna.

"People have been excited about thermoelectric generators, but there are many limitations on getting a system that works effectively," he said. "We believe that the rectenna technology will be the best approach for harvesting heat economically."

In future work, the research team hopes to optimize the antenna operation and improve their theoretical understanding of how the rectenna works, allowing further optimization. One day, Cola hopes the devices will help accelerate space travel, producing power for electric thrusters that will boost spacecraft.

"Our end game is to see carbon nanotube optical rectennas working on Mars and in the spacecraft that takes us to Mars," he said.

This work was supported by the Army Research Office under the Young Investigator Program agreement W911NF-13-1-0491 and the National Science Foundation Graduate Research Fellowship program under grant DGE-1650044.

Published March 2018

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