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How Terminal Block Contacts Work

Quick-connect type terminal block contacts consist of a flat blade or a simple tab with a design that accepts a push-on connector holding the end of a wire. A force-fit metal sleeve pushed over the tab makes the contact. Such quick-connect type terminal blocks are meant for thin wires up to AWG 12.

Tubular contacts are a length of rectangular metal tubing, with screws threaded through the top of the tube at both ends. In tubular screw contacts, the flat bottom of the screws secures the inserted wires by providing pressure on them. Tubular clamp contacts use a pressure plate between the screws and the wire to apply pressure on the wires. The screws usually hold the pressure plates captive, which makes tubular clamp contacts useful for fine stranded wires.

Feed-through contacts have mounting surfaces with studs going through them. Feed-through contacts are useful for wire leads passing through a wall under a block directly or very close to the wall. Stud contacts or strap-screws secure the wires for connection.

For installations that must stay connected even during shock and vibration, dead-front connectors with two-part plug-ins are very useful. For multiple points of contact on posts, quality connectors typically use socket-mating springs. Wire protectors made of beryllium-copper protect both single and multi-stranded wire terminations. Flush-mount designs for boards are best for minimizing stress on solder joints when tightening screw terminals.

Flat metal strap with screws through each end make up strap-clamp contacts. The screw heads usually have a wire-clamping element under them for exerting pressure on the wires. These contacts require the insertion of bare wires within the pressure contact.

Strap-screw contacts are similar in construction to the strap-clamp contacts but without the wire-clamping elements. The user simply loops the wires over the screws or may attach a ring or spade lug on them. Tightening the screws on the loop, ring, or spade lug serves to secure and connect them.

Fuse blocks usually consist of a fuse in series with a circuit. Usually, there are contacts at each end, like that of standard blocks. It is possible to insert a cartridge-fuse pug into clips connected to each contact. Apart from circuit identification, this arrangement facilitates easy fuse changing.

Plane and rigid insulating members can mount multiple one-piece blocks for connecting one or more circuits. There may be open barriers facilitating easy contact accessibility. Other variants may offer contact protection through closed barriers or dad fronts. A single base may hold standard units of 2, 4, 6, 8, 10, or 12 circuits.

Terminal block contacts may also be of the short-circuit type, like the one-piece blocks. Short-circuit contacts require a screw short-circuiting two strips, allowing current flow into the desired circuit by direct connection or by shunting out other circuits.

Section blocks usually come with individual molded units containing contacts. It is possible to form any desired number of circuits by assembling them together with end barriers in between. Formation of preassembled lengths requires snapping off or adding sections in the desired number of groups of contact sections to form a sectional terminal block assembly.

Stepper Servo Motors

Although many designers prefer to relegate stepper motors to the realm of low-cost low-performance technology, a new technique is bringing the step motors a fresh lease of life. This new drive technique is the stepper servo, and it uses the generic stepper motor, yet extracts significantly more performance out of it. The technique requires adding an encoder and operating the motor effectively as a commuted two-phase brushless DC motor.

While the inclusion of an encoder makes the stepper servo idea non-suitable for low-cost applications, designers are increasingly considering the technique an alternate approach to applications requiring a brushless DC motor.

This is because the cost of a stepper servo motor is considerably less than a comparable brushless DC motor, while the former actually outperforms brushless DC motors in areas of torque output and acceleration. Therefore, designers are considering the stepper servo motor as a candidate for high-speed applications such as coil winding, point-to-point moves, textile equipment, high-speed electronic cams, and more.

Stepper motors are easy to use, making them popular. They maintain their position without external aids such as encoders. Neither do they require a servo control loop when designers use them for positioning, as other DC motors do. Their brushless operation, high torque output, and low cost are their biggest advantages. However, their limited speed range, noisy operation, and vibrations are their main disadvantages.

Being a multi-phase device, stepper motors require the excitation of multiple coils and driving control waveforms for their operation. The usual configuration for stepper motors will have 1.8 mechanical degrees for a full step of 90 electrical degrees—making it 200 full steps for every mechanical rotation. Other stepper motors may have 7.2- or 0.9-degree configurations in place of the customary 1.8.

A stepper servo motor has an encoder attached to the shaft. For a typical 1.8-degree stepper motor, the resolution of the encoder must be of the order of 2000 counts per mechanical rotation. The encoder verifies the final position of the rotor through a traditional step motor control scheme.

The stepper servo motor operates more like a brushless DC motor, with the actual encoder position commuting the phase angle, instead of the commanded position. The phase angle and amplitude of the driving waveform need to vary continuously depending on the output from a position PID loop. This allows the motor to servo to the commanded position.

The presence of the encoder frees the stepper servo from losing steps—the encoder determines the location. The motor operation is now more efficient, causing much lower heat generation. Traditional stepper motors require driving at large currents adequate for handling worst-case motions.

Traditional stepper motors always have problems achieving positional accuracy. With the encoder driving the stepper servo motor to its location, these vagaries of position do not arise. The encoder frees the stepper servo motor from the restrictions of the 1.8 degrees per step of the regular stepper motor. Simply increase the resolution of the encoder to get better positional accuracy.

The addition of the encoder also produces a smooth acceleration to the desired position without the customary bouncing and noise.

Small LED Driver IC

Although Switch-mode and PWM or Pulse Width Modulation methods make very efficient drivers for LEDs, they are also a good source of electromagnetic noise. Many applications require low noise conditions for proper operations, especially those related to medical. These low-noise applications benefit from linear circuits that introduce far lower noise in the system as compared to the Switch-mode or PWM topologies.

For driving LEDs linearly, Infineon Technologies AG offers a small LED driver IC, the BCR431U. Available in a tiny SMT package SOT23-6, the BCR431U can regulate the operating current to the LED in a standalone operation without requiring the help of an external power transistor.

Operating between a voltage range of 6 to 42 VDC, the BCR431U can drive LED currents up to 37 mA. A high-value resistor connected between the pins Rset and RS of the IC allows setting the desired LED current level.

The major advantage of the BCR431U LED driver is its low-drop feature. At a full load of 37 mA, the IC drops only 200 mVDC across from the supply to the output. At 15 mA load, this voltage drop is only 105 mVDC. This feature has two benefits—one, the power dissipation in the driver IC at full load is only 7.4 mW, and two, the user can drive a string of LEDs in series connection mode by adjusting the input voltage. Over the entire current range, the driver IC maintains precision of ±10% of the set value of the LED current.

The low voltage drop across the BCR431U LED driver improves the system efficiency substantially while allowing extra voltage headroom to compensate for the tolerances of forward voltages of LEDs. Therefore, even if some LEDs in the string have different forward voltages, the driver IC can accommodate them with an increase or decrease in the driving voltage. Likewise, it can accommodate tolerances in supply voltage sources when used in multiple applications.

Internal circuit configurations ensure the BCR431U LED driver IC can keep the LED current under control, even when the temperature changes. If the junction temperature of the driver IC rises, a temperature controlling circuit within the IC reduces the LED current, thereby helping to bring down the junction temperature. Therefore, the BCR431U can protect itself from thermal runaway.

The linear low-drop LED current driver IC BCR431U is eminently suitable for driving long strips of low-power and low-voltage LEDs. Highly flexible in adjusting to 12, 24, or 36 VDC power supplies, the driver IC offers high precision and efficiency when driving LEDs. Internal thermal protection built into the driver IC ensures long-life operations, preventing accidental damages and protections against surge events. Infineon has designed the IC BCR431U to be robust enough to withstand high ESD conditions.

Applications for BCR431U are almost endless including driving LED strips, LED channel letters and displays, architectural LED lights and displays, emergency lights, retail lights for decoration, shop window LED lights, and many more. The driver IC is especially helpful in shops for driving LED lights in shops showcasing items in different colors.

High-Speed Ceramic Digital Isolator

Isolated systems can communicate digitally among themselves without conducting ground loops or presenting hazardous voltages—simply by using digital isolators. A capacitive isolation barrier exists between the isolated systems. The transmitter side modulates its digital data with a high-frequency signal that allows it to transmit across the capacitive isolation. Receivers on the other side detect the signal, demodulate it to extract the digital data, and use it.

Digital isolators offer thick insulation distances of greater than 0.5 mm, with reliable high-voltage insulation. ON Semiconductor has patented an off-chip galvanic capacitor isolation technology and offer a full-duplex, high-speed, bi-directional, dual-channel digital isolator—the NCID9211.

NCID9211 supports isolated communications. Therefore, isolated systems do not need conducting ground loops to communicate with digital signals, and it is possible for them to avoid hazardous voltages. The optimized IC design and the off-chip galvanic capacitor isolation technology that ON Semiconductors has developed ensures high noise immunity and high insulation. The power supply rejection and common-mode rejection ratio specifications of the NCID9211 support this. Compared to coreless transformers and thin-film on-chip capacitors, the thick film substrates offer capacitors with 25 times the dielectric thickness.

The digital isolator offers a unique combination of an insulating barrier and an electrical performance along with safety and reliability that only optocouplers had offered so far. NCID9211 comes in a 16-pin small outline package with a wide body. The device has features with several advantages.

NCID9211 is the only digital isolator in the market today that includes insulation reliability matching that offered by optocouplers while offering the same level of safety. The device has a distance through insulation or DTI or over 0.5 mm and uses off-chip capacitive isolation for achieving maximum high-voltage insulation reaching 2000 Vpeak.

The off-chip capacitive isolation offers better long-term reliability and safety compared to other digital isolation methodologies available in the market. ON Semiconductors guarantees the specifications of the NCID9211 over a supply voltage range of 2.5-5.5 DVC and an extended temperature range of -40 °C to +125 °C. The device does not require overdesign as the device performance remains stable over voltage and temperature.

NCID9211 offers a high-speed communication of NRZ or non-return to zero data at rates of 50 Mbits per second. The maximum propagation delay is only 25 ns, while the maximum distortion of the pulse width is only 10 ns.

ON Semiconductor claims NCID9211 has better performance over optocouplers. Compared to optocouplers, NCID9211 does not exhibit insulation material wear out over time up to 1500 V, there is no LED to degrade over time, and the performance across devices is more consistent. Compared to optocouplers, NCID9211 has a longer lifetime expectancy.

With a minimum common-mode rejection of 100 KV/µs, the NCID9211 has a superior noise immunity and it meets stringent performance requirements of EMI/EMC. However, for meeting reliable high-voltage insulation requirements, there must be a minimum creepage and clearance distance of 8 mm between the input and the output.

With full-duplex and bi-directional communication, the NCID9211 has several applications such as isolated PWM control, SPI and I2C type micro-controller interfaces, voltage level translators, isolated data acquisition systems, and many more.

Pyroelectric Sensors

Certain crystalline substances are electrically polarized, and a change in heat causes them to change their polarization proportionally. The crystal manifests its change in polarization by temporarily generating a detectable voltage across itself. Scientists call the behavior of such crystals the Pyroelectric effect and the phenomenon as Pyroelectricity. Sensors made of such crystals are pyroelectric sensors and they are infrared sensors with a host of applications with the underlying technology relying on the pyroelectric effect.

With pyroelectric sensors, it is possible to detect infrared radiation or heat emanating from substances. Different materials and chemicals absorb infrared radiation at specific wavelengths. Therefore, pyroelectric sensors can detect the presence of a specific material or chemical by sensing the change in a specific wavelength of IR that the substance is blocking. Two basic types of pyroelectric sensors are available—passive and active.

Passive pyroelectric sensors can measure or detect infrared rays that an object generates as an IR emitter. Active pyroelectric sensors require the presence of an absorber between itself and the IR source, to be able to detect the wavelengths that the absorber is absorbing. The industry uses pyroelectric sensors primarily to detect motion, gas, food, and flame, among others.

Motion sensing can use either active or passive pyroelectric sensors. Active pyroelectric sensors are useful in instances where the emitter and sensor are far apart over a very long distance. A garage door safety sensor is a simple example. Anything blocking the infrared signal across the opening of the door sends a signal to stop it from lowering. Passive pyroelectric sensors can be very sensitive in detecting the source of heat directly, such as from a human body. The user can configure the sensor to detect the presence or absence of any object, including a human body, radiating enough IR.

Monitoring and detecting the presence of gasses is another popular application for pyroelectric sensors. The setup requires the presence of an IR emitter and an active sensor across a sample of the gas. The pyroelectric sensor checks for the presence of a specific wavelength—the absence of which means the gas absorbing the specific wavelength is present in the sample. Using optical IR filters, manufacturers can tune the sensors to a specific wavelength, permitting only that wavelength to pass through to the sensing element.

Like pyroelectric gas sensors, manufacturers can calibrate pyroelectric food sensors to detect food-related substances. For instance, pyroelectric food sensors can differentiate between fat, lactose, and sugar, as they absorb different IR wavelengths. In fact, these general pyroelectric sensors are useful for monitoring many types of commercial, industrial, and medical substances or processes, depending mainly on their configuration.

Pyroelectric flame sensors can easily detect flames as they are strong emitters of IR. They are useful not only in detecting the presence of flames, pyroelectric sensors can also differentiate between sources of flames. Triple IR flame detection systems do this by comparing three specific IR wavelengths, and their ratios to each other. This helps to detect flames to a high degree of accuracy—very useful in fire protection systems and in smart homes, furnace monitoring, and forest fire detection.

Coreless Magnetic Current Sensors

Modern industrial drives require accurate current measurement for effectively regulating the torque and ensuring maximization of operational efficiency levels. For achieving necessary efficiency levels along with the safety requirements, the measurement methodology must achieve a high degree of linearity and respond rapidly. This is especially true for detecting conditions such as short-circuit and over-current. For instance, it is necessary to arrest the fault condition from an over-current situation within 3us or less. The detection, evaluation, and triggering process must occur within 1 us or less. Therefore, it makes tremendous sense to include this capability within the current sensor.

A popular current measuring scheme involves using a shunt resistor in series with the current under measurement. However, this involves insertion loss, with the resistance of the PCB track, solder joints, and wiring contributing to the loss in addition to that from the shunt resistance. The design becomes more complex if the shunt resistor requires galvanic isolation between control electronics and power output stages.

A better alternative is the magnetic current sensor, primarily based on Hall effect and using core-based or core-less sensing. Being non-resistive, magnetic current sensors involve an insertion loss of a far lower amount. Moreover, magnetic current sensors are contact-less, thereby providing inherent isolation between low voltage and high voltage circuits.

A current flowing through a conductor generates a magnetic flux. A core-based sensor typically concentrates the flux in its ferromagnetic core. The open-loop configuration of the sensor typically uses a sensing element within the air-gap, where the flux concentration is the maximum. This arrangement can have hysteresis and temperature drift errors.

The closed-loop configuration has a compensation winding with current flowing in the opposite direction to minimize the hysteresis and temperature drift errors. Although providing very precise current measurements, the approach is complex and the introduction of the compensation winding generates additional power losses.

In contrast, a core-less sensor does not use a ferromagnetic core, thereby avoiding the hysteresis and temperature drift errors altogether. Current measurement now depends totally on the magnetic field that the current-carrying conductor generates. Although the flux density that the wire generates is much lower, modern electronics design easily compensates for this.

Like the core-based sensor, the core-less sensor also has an open-loop and a closed-loop design. In closed-loop sensing, compensatory windings equalize the flux density and use Hall element sensing. The open-loop sensing uses highly linear Hall elements. Therefore, closed loop sensing does not depend on the linearity of its Hall elements.

With core-less sensors using very low levels of flux density, industrial environments with EMI often makes it difficult to measure the current accurately. Shielding improves the situation to a certain extent, but may not be totally adequate.

A differential measurement approach resolves the situation. This requires a suitable conductor structure along with the presence of at least two sensor elements arranged with their sensitivities in perpendicular. If the electrical connection has the polarities of the sensors opposing each other, and the positioning of the elements above the conductor is symmetrical, they effectively cancel the common-mode component of any external stray fields that may disturb the current measurement.

Intelligent Phase Control for BLDC Motors

Many applications use BLDC or Brushless DC motors for powering several types of high-speed equipment. These include industrial machines, data center cooling fans for servers and home vacuum cleaners. One of the challenges designers face is to ensure the motors operate effectively and reliably. Now, Toshiba is making it easy for designers to do this with its intelligent phase control motor controller.

While other manufacturers also offer intelligent phase control devices, they usually meet a specific design need. Toshiba’s TC78B016FTG has a driver rated for 40 VDC and 3 A maximum. The fully integrated motor control driver requires a power supply ranging from 6 to 36 VDC, and provides a sine wave output drive. ON resistance of the driver is only 0.24 ohms, representing the total of low and high sides. This typically reduces the self-heating of the device during operation and allows driving 1 to 1.5 A loads without a heat sink.

TC78B016FTG uses a simple speed control mechanism using pulse width modulation. It has several built-in protections, and these include protection from over-current, thermal runaway, and motor lock. Toshiba offers the TC78B016FTG in a 5 x 5 mm VQFN32 package.

Other controllers from Toshiba include the TC78B941FNG and TC78B042FTG. These intelligent phase controllers allow users to tailor the power requirement of an application by selecting a proper MOSFET and its gate driver for the design. Toshiba offers these devices in SSOP30 and VQFN32 packages respectively. Both measure 5 x 5 mm.

Another controller from Toshiba is the TC78B027FTG, which incorporates a gate driver, for which the user can select the proper MOSFETs according to the application. This controller also has a one-Hall drive system for the user to drive a less expensive one-sensor BLDC motor. Toshiba offers the device in a VQFN24 device measuring 4 x 4 mm.

Conventional drive technology adjusts the phase or lead angle of the voltage and current it feeds to the motor for achieving high-level efficiency. However, high-speed rotation prevents the magnetic drive from reaching maximum power, as phase lag delays the voltage applied to the coil from rising until the current has increased to a maximum.

Intelligent phase controllers avoid the above situation by advancing the rotor by a certain angle from the calculated position. This is the new lead angle that depends on the BLDC motor’s characteristics, its rotational speed, and load conditions.

Designers try to achieve optimal efficiency over rotational speeds ranging from almost zero rpm at motor startup to several thousand rpm at high speeds. As this requires several characterizations for adjusting the phase, they achieve optimal efficiency only for a limited range of speeds. Intelligent phase controllers allow BLDC motors to rotate at high speeds with uniform accuracy and efficiency.

Compared to earlier technologies, the approach taken by Toshiba is different. Rather than adjust the phase difference between the voltage and current to the motor at different points in its operating range, Toshiba automatically and continually adjusts the phases of voltage and current the controller feeds to the motor. Intelligent phase controllers from Toshiba thereby achieve the highest possible efficiency for the entire operating range of the motor.

What is Edge Computing?

Many IT professionals spend most of their careers within the safe and controlled environments of enterprise data centers. However, managing equipment in the field is a different ball-game altogether.

Pandemics such as the COVID-19 are increasingly transforming the world. The emerging ecosystem is confronting and challenging this transformation. Among this mayhem, edge computing is entering as a key transition phase, with the massive shift towards home-based work. Along with the generation of new opportunities for distributing computing, key players are deploying increasing numbers of edge data centers for navigating the sharp economic downturn.

The major benefit of edge computing is it acts on data at the source. This distributed computing framework works by bringing enterprise applications closer to sensors acting as data sources within the IoT system and connecting them with local edge servers and cloud storage systems. Edge computing can deliver strong business benefits with its better bandwidth availability, improved response times, and faster insights.

Edge computing has the potential to enable new services and technologies with its low-latency wireless connectivity. This could transform global business and society. According to some technologists, edge computing can bring in a new era of powerful mobile devices with no limit on their ability to compute power and data.

Consultants and futurists are projecting a growth of up to US$4.1 trillion for the edge economy by 2030. Linux Foundation, in their report Edge 2020 claim edge investment will take wing after 2024, and the power footprint of the deployed edge IT and data center facilities reaching 102, 000 MW by 2028. They expect the annual capital expenditures to reach US$146 billion by then.

In the technology world, however, there are divided opinions regarding the short-term prospects of edge computing. Although there is no doubt about the usefulness of edge computing, people are skeptical about the time frame for edge computing to become profitable. Therefore, starting with 2020, investors and end-users are looking intently at the economics of edge computing and focusing more on its near-term cost-benefits rather than on its long-term potentials.

There is a huge opportunity in edge data centers, as edge computing plays out over several years, with long deployment horizons and gradual adoption of technologies boosting the market. However, executives do not expect the revolution to go through cheaply, with the build-out of edge computing pressurizing the economics of digital infrastructure. This may create repeatable form factors leading to more affordable deployments. Experts are confident that most edge data facilities will be highly automated, remotely managed, and require no human intervention.

At the present, it is difficult to say which edge projects will succeed. With product segmentation and a fluid ecosystem, even promising ventures can struggle as they try to locate profitable niches. While investors are wary of speculative projects, it is reasonable to expect well-funded platform builders and stronger incumbents will acquire promising edge players, especially those running short of funding.

Tower operators are also influencing the competitive landscape. Their massive real estate holdings and financial strengths are positioning the tower operators as potentially important players in the edge computing ecosystem.

Electronics for Indoor Farming

With global population growth, there is increasing concern over the sustainability of ecologically friendly farming. Farmers are now adopting innovative technologies for improving the overall efficiency of farming. Among them, the Internet of Things or IoT shows a greater promise with real-time, wireless, and remote sensing, monitoring, and control of indoor farming conditions and operations, such as humidity, moisture levels, soil pH, temperature, and lighting.

Most of the functions mentioned involve complex combinations with farmers often struggling to combine LED lighting, wireless communications, actuators, and sensors with control and mobile applications for gathering the optimum information, analyzing it quickly to generate the appropriate response, and acting upon it. Even for the technologically proficient, implementing existing product offerings is a challenge for deploying a low-power, scalable, cost-effective, reliable, and secure system.

Arrow Electronics, in combination with eInfochips and Analog Devices, offers an end-to-end, one-stop solution for the above problems in the form of the Grow House Evaluation Kit. Their starter kit has the best of technologies, including power management, converter, and signal conditioning from Analog Devices. The kit comes with sensors for moisture and pH, wireless connectivity, LED lighting with a dimming facility, along with remote accessibility via a cloud-based dashboard. All these are available on the iOS and Android platforms.

The Grow House Evaluation Kit is a smarter way to set up indoor farming operations. With wireless connectivity from Silicon Labs, LEDs from OSRAM Light Engine with dimming and color control, the cloud-based dashboard provides remote accessibility for moisture and soil pH levels through ruggedized connectors from Amphenol.

The soil-monitoring node included with the Grow House Evaluation Kit uses leading-edge technologies from Analog Devices. Included in this soil-monitoring node are the power and analog solutions for measuring the pH and moisture levels of the soil with high accuracy for maximizing crop yield.

The IoT gateway included with the kit is based on a platform from Qualcomm 96Boards. The LED node in the kit features the ability to control the color output, intensity, and the UV spectrum of the custom light engine.

Pre-certified ZigBee modules from Silicon Labs implemented with the IoT gateway provides custom control of the LED and Soil nodes. Arrow Electronics offers mobile applications compatible with iOS and Android platforms for configuration and control of the LED and Soil nodes. Arrow Electronics also offers a light engine with OSRAM OSLON Square high-power LEDs, along with design files for customization, but the LEDs are only for demonstration.

Those looking for the complete Growhouse Platform need to order three nodes independently for configuration of the Growhouse. These are the LED Node, IoT Gateway, and the Soil Node.

Vertical farming operations benefit extensively from digital transformation solutions from Arrow Electronics, thanks to their advances in technologies involving sensors and connectivity, and easy access to cloud infrastructure providing cost-effective operations. Although timer-controlled pumps, lighting, and fans do help in farming, digital transformations such as those provided by the Growhouse Platforms go far beyond the simple methods. A digital grow house based on the Grow House Evaluation Kit enables this transformation in the easiest way possible.

Future of LEDs

LEDs have much to offer—small size, high efficiency, and incredible versatility—no wonder they are the most popular electronic products in the market today. Their versatility allows us to use them in horticulture, as status indicator lights, and displays with high definition. Although we are so familiar with LEDs that we hardly notice them anymore, new applications keep appearing, and engineers are forever making newer breakthroughs. That is why the LED market is still growing at a stupendous rate, especially in Europe, India, and Southeast Asia. We have listed some new technologies here:

Multicolor LEDs

After several tries, scientists have recently been able to achieve an LED that produces a blue color. This has completed the entire spectrum of LED arrays. Now, scientists have a technique that allows a single LED to produce all three primary colors. So far, rendering a full spectrum required placing three to four tiny LEDs near one another. The new technique has a big implication of making multicolored displays with color-tuned LEDs.

Furthermore, the new process dopes gallium nitride with europium, a rare earth element, and the process is compatible with current technologies involving GaN. Commercial solid-state lighting commonly uses GaN LEDs, which means we will see the new technology working in the commercial sector very soon.

Cooling with Reversed LEDs

LED physics has another significant new development. Running LEDs in reverse creates a cooling effect. A research team has demonstrated that by running LEDs backward, it is possible to achieve a tiny cooling effect of the order of 6W/m². This is contrary to the situation in a reverse connected diode, where the diode does nothing.

Researchers are of the opinion they can improve the cooling capacity to 1000W/m². Although the idea is not yet ready for practical implementation, wearables and mobile devices may benefit from the improved performance from using LEDs to remove heat from processors.

Lighting for Horticulture

Horticulture is benefitting from LED temperature effects and color-tuned lighting. Tomato growers in Belgium have used LEDs to stimulate plant growth. Rather than high-pressure sodium vapor (HPSV) lamps, as is the industry standard, the farmers used LED lighting for their entire 13.3-acre indoor tomato farm.

Although the light from the LEDs appears pink to human eyes, it is actually a mix of red, infra-red, blue, and white LED lights, which the farmers have mixed perfectly for stimulating tomato plant growth. Using Hyperion fittings, the farmers have used new LEDs from Cree. Now, farmers in the UK and the Netherlands are also using these new horticultural LED lamps.

The Belgian farmers were initially skeptical about using LEDs, as these have high efficiency and produce greater amounts of light than heat. They felt LED lights will not provide adequate heat during winter to keep the plants warm. However, they did not need their back-up heating system in the first winter. This proves developments in lighting is effectively reducing payback periods.

The future for LEDs looks bright, with new sources of innovation and recent technological development bringing increasingly superior practical use. Expect more new and improved products in our daily lives with these new LEDs, especially those in color tuning.