Showing posts with label LED Circuit. Show all posts
Showing posts with label LED Circuit. Show all posts

LED-Circuit

LED circuit
Simple LED circuit diagram




In electronics, the basic LED circuit is an electrical circuit used to power a light-emitting diode (LED). It consists of up to four components connected in series: a voltage source, a current limiting resistor, a LED, and optionally a switch to open and close the circuit. The switch may be replaced with another component or circuit to form a continuity tester Two diodes may be placed in parallel in the circuit, but connected anode to cathode; the second diode may be used to protect the LED against reverse bias, which can damage the LED, or it may be another LED which is illuminated when the polarity of the voltage source is reversed.

The LEDs used will have a forward voltage specified at the intended operating current. When the voltage source Ohm's law is used to calculate the resistor that is used to attain the correct current.[4][5] The resistor value is computed by subtracting the forward bias voltage from the supply voltage, and then dividing by the desired operating current.
This basic circuit is used in a wide range of applications, including many consumer appliances.

The formula to use to calculate the correct resistance for resistor to use is:

RESISTANCE(Ohms) =
(POWER SUPPLY VOLTAGE-LED VOLTAGE DROP)/LED CURRENT RATING


where:
Power supply voltage is the voltage of the power supply (such as a 9 volt battery)
LED voltage drop is the voltage drop across the LED (typically about 1.7 - 3.3 volts; this varies by the color of the LED)
LED current rating is the manufacturer rating of the LED (usually given in milliamperes such as 15 mA)

Audi R8 - First full-LED headlamps



Audi announced that effective immediately, options available for the Audi R8 will also include the first full-LED headlamp. The daytime running light now features 24 LEDs per headlamp along with light-emitting diodes for turn signals and low-beam and high-beam headlights.

Audi introduced a strip-shaped fog lamp at the Detroit Auto Show in 2003. Following which, the Audi Nuvolari quattro featured the first full-LED headlamp at the Geneva Auto Show

The option will run you €3,590 (or $5,585 on the stateside), which we think is way too expensive. We doubt anyone would look at your R8 and go “Oh man you didn’t opt for the full-LED headlamps?” Well, unless we’re checking out your car - then we’d just make you feel bad about not cashing out almost $6,000 for full-LED headlamps.

First full-LED headlamp for the Audi R8

- 54 high-performance LEDs provide all lighting functions
- Color similar to daylight offers advantages at night
- Innovative lighting technology as an option

Ingolstadt – Effective immediately, the range of equipment available for the Audi R8 sports car now also includes the first full-LED headlamp. In addition to the daytime running light which now features 24 LEDs per headlamp, light-emitting diodes are also used for the turn signals, the low-beam and the high-beam headlights. The €3,590 option rounds out the list of equipment available for the high-tech, mid-engine sports car.

The earlier launch of LED technology at the front of the car required a waiver by the European Union. The prominent advantages are lower energy consumption and a color that more closely resembles daylight, provides greater contrast and is easier on the human eye. LEDs are also non-wearing, require a lower voltage, are compact and offer greater design freedom.

The new full-LED headlamp represents the pinnacle of Audi’s lighting strategy. The use of LEDs already enjoys a long tradition. This innovative technology has previously been used in production vehicles for tail light functions, brake lights and daytime running lights. Since early 2003, Audi has also used the semiconductor technology in a number of concept cars to implement some or all of the lighting functions at the front of the car.

The brand with the four rings first introduced a strip-shaped fog lamp at the Detroit Auto Show in 2003. That same year, the Audi Nuvolari quattro showing the first full-LED headlamp was a highlight of the Geneva Auto Show. And the Le Mans quattro – a legitimate predecessor to the Audi R8 – illuminated the Frankfurt night with LEDs on the eve of the 2003 Frankfurt Auto Show.

Additional concept cars and many refinements to the light source and headlamp geometry followed. This technological highlight is now available as an option for the Audi R8, where it joins other very well-known high-tech components such as the aluminum Audi Space Frame, ceramic brakes and the mid-mounted V8 engine with FSI technology.

Led-World Exclusive - All-LED-lights Mercedes-Benz CL on 2011 Shanghai Auto Show



"Innovation for Tomorrow" is the slogan of the fourteenth session of the Shanghai auto show. Based on this concept, the auto show brings many new technologies to the first facing the public. Mercedes-Benz CLS enjoys its debut on the auto show. Its 71 LED lights design makes it the focus. 2011 Shanghai Auto Show

LED has been used in automotive lighting for some time, but now there are only two kinds of vehicles applying the all-LED headlights: Mercedes-Benz CLS and Audi A8. According to manufacturers, those Audi A8 sales domestically use Xenon headlights and all LED lights are only options. Then here are the questions: What about all LED headlights? Will them become the future mainstream?

Currently, a single LED light source intensity is still less than xenon lamps. Among the majority of the car lights, LED lamp only plays a supporting role for Xenon Headlights. To reach the same brightness, even high-brightness LED requires an additional group LED lights comparing with the xenon lamps. And this group of high-brightness LED costs much and release much more heat than xenon lights.

However, the manufacturers tell us that, through some special power conversion device, LED light can issue different color temperature. The car headlights of Mercedes-Benz CLS can transform the color temperature under certain conditions and can be used as fog lights. Audi A8's daytime running lights can be converted into turn signals.

At present, LED lights have been widely used as auxiliary lights for vehicles. In turn lights, fog lights, and many other places LED Lights have replaced other sources. However, the high cost of LED brightness and thermal are the problems that R & D personnel facing. LED lighting as the main front Car Headlights is still immature. If this bottleneck breaks, LED will be the future of the automotive field.

Now, if you want to replace your car headlights, HID Xenon Car Headlight Kits are still your best option. They are providing driver better visibility and nigh vision for safety concern. NearbyExpress.com is a professional wholesaler and dropship supplier of Car Eletronics. The products are now at low China wholesale price for all its clients.

Salute to Father of LED


Nick Holonyak
Zeigler, Illinois; 1928

NICK HOLONYAK, JR. was born in Zeigler, Illinois on November 3, 1928. he attended the University of Illinois and received a B.S. (1950), M.S. (1951), and Ph.D. (1954) in Electrical Engineering. A Texas Instruments Fellow, he was John Bardeen’s first student. He later was employed as a member of technical staff at Bell Telephone Laboratories (1954-55) and helped demonstrate feasibility of diffused-impurity silicon devices, including transistors, oxide-masked transistors, p-n-p-n switches and SCR’S. He served with the U.S. Army Signal Corps (1955-57) at Ft. Monmouth, New Jersey, and at Isogo-ku, Yokohama, Japan. In 1957 he joined the Advanced Semiconductor Laboratory of the General Electric Company (Syracuse) and made contributions in the areas of power and signal p-n-p-n devices (including invention of the shorted-emitter and symmetrical SCR and thyristor switches—TRIAC’s, etc.), tunnel diodes, phonon-assisted tunneling (the initial observation of inelastic tunneling and the beginning of tunneling spectroscopy), halide transport and first epitaxial growth of III-V compounds and compound mixtures (including heterojunctions, 1960-63), double injection and deep-impurity-level effects, junction luminescence (GaAsP LED’s), and III-V alloy semiconductor lasers (visible spectrum, GaAsP, 1962). His work from 1960 to 1962 on GaAsP and the initial construction in 1960 of a p-n junction in the crystal system, and a visible-spectrum (red) laser in 1962, led to the commercial introduction of red GaAsP LED’s (and eventually to the concept of an “ultimate lamp”). He is the inventor of the first practical light emitting diode (the GaAsP LED), which also marks the beginning in the use of III-V alloys in semiconductor devices (including heterojunctions.)

Since 1963 he has been a professor at the University of Illinois in the Department of Electrical and Computer Engineering and is a member of the University of Illinois Center for Advanced Study. He and his students have worked primarily on III-V semiconductors, III-V alloy crystal growth and the demonstration of red-orange-yellow-green stimulated emission in In1-xGaxP, In1-xGaxP1-zAsz and A1xGa1-xAs1-yPy, stimulated emission on nitrogen trap transitions in the alloys GaAs1-xPx and In1-xGaxP, and heterojunctions in various ternary III-V’s and in the quaternaries A1xGa1-xAs1-yPy and In1-xGaxP1-zAsz. He and his students were the first to make quaternary III-V semiconductor devices (LEDs and lasers.) Since 1976 he has been concerned with quantum-well (QW) light emitters and lasers, and with impurity-induced layer disordering, which shifts lower gap quantum well layers to higher gap bulk crystal and serves as a basis for integrated optoelectronic devices. In 1990 he and his students introduced (~400˚C) stable native oxides on, and buried in, Al-bearing III-V compounds and demonstrated their use in optoelectronic devices (LEDs and lasers). He and his students were the first (1977) to construct p-n diode quantum well lasers (InP-InGaAsp, LPE) and were the first to achieve (1978) continuous (cw) room temperature (300 K) laser operation of quantum well heterostructures and superlattices, and later (1982) strained layer quantum well heterostructures. They are the source of the name “quantum well laser.” Most recently (with Dupuis, 2001) he introduced tunneling-coupled quantum-well-assisted quantum-dot lasers, and (with Feng, 2004) the light-emitting three-port operation of heterojunction bipolar transistors, including QW-based HBTs and, after 57 years, a transistor laser.

He is co-author of the book SEMICONDUCTOR CONTROLLED RECTIFIERS (Prentice-Hall, Inc., 1964) and PHYSICAL PROPERTIES OF SEMICONDUCTORS (Prentice-Hall, 1989), editor of the Prentice-Hall series “Solid State Physical Electronics,” and has served on the Editorial Board of the PROCEEDINGS OF THE IEEE (1966-1974), SOLID-STATE ELECTRONICS (1970-1991), and JOURNAL OF APPLIED PHYSICS and APPLIED PHYSICS LETTERS (1978-1980). He received a General Electric Cordiner Award (1962), and for his contributions to the field of visible-spectrum light emitting diodes and diode lasers, he is the recipient of the IEEE Morris N. Liebmann Award (1973), the John Scott Medal (1975, City of Philadelphia), the first GaAs Symposium Award with Welker Medal (1976), the IEEE Jack A. Morton Award (1981), the Electrochemical Society Solid State Science and Technology Award (1983), the Sigma Xi Monie A. Ferst Award (1988), the IEEE Edison Medal (1989), the Charles Hard Townes Award of the Optical Society of America (1992), the National Academy of Sciences Award for the Industrial Application of Science (1993), American Electronics Association 50th Anniversary Award (1993, “Inventing America’s Future”), American Society for Engineering Education Centennial Medallion (1993), Vladimir Karapetoff Eminent Members’ Award of Eta Kappa Nu (1994), TMS John Bardeen Award (1995, The Minerals, Metals, and Materials Society), 2000 IEEE Third Millennium Medal, Frederic Ives Medal of the Optical Society of America (2001), the IEEE Medal of Honor (2003), the Washington Award (Western Society Engineers, 2004), the Lemelson-MIT Prize (2004), and the MRS Von Hippel Award (2004). In 1990 he received the U.S. National Medal of Science and in 2003 the 2002 U.S. National Medal of Technology. In 1992 he received from Northwestern University an honorary doctor of science degree and was elected an honorary member of the Ioffe Physical-Technical Institute (St. Petersburg, Russia). In 1994 he received an honorary doctor of engineering degree from Notre Dame University, in 1995 the Japan Prize, and in 2003 the Global Energy International Prize (Russia). In 1993 he was appointed (University of Illinois) the John Bardeen Chair Professor of Electrical and Computer Engineering and of Physics, a chair sponsored by the Sony Corporation. He is a member of the National Academy of Engineering (1973), a member of the National Academy of Sciences (1984), foreign member of the Russian Academy of Sciences (1999), eminent member of Eta Kappa Nu (1998), fellow of the American Academy of Arts and Sciences (1984), fellow of the IEEE (life fellow, 1994), fellow of the American Physical Society, fellow of the Optical Society of America, fellow of the American Association for the Advancement of Science (2003), and laureate of the Lincoln Academy of Illinois (2005). In 2008 he was inducted into the U.S. National Inventors Hall of Fame.


Semiconductors, quantum well and dot lasers, LEDs, transistor lasers, optoelectronics

Professor Holonyak has made fundamental contributions to the science and technology of elemental and compound semiconductors, including major achievements in solid-state lasers and incoherent light emitters. He invented the first practical light-emitting diode and is the first to make III-V alloy devices (III-V alloys now part of all high performance lasers and LEDs, U.S. Patent #3,249,473). He and his students built the first p-n diode quantum well lasers and introduced the name quantum well lasers (also vital now in all lasers and LEDs). He is known also for his work on early diffused silicon devices, tunnel diodes, and silicon-controlled rectifiers, including invention of the symmetrical switch. (TRIAC) used in wall light dimmers. He was the first to observe inelastic tunneling, which is the beginning of tunneling spectroscopy. Among the 39 patents he holds on semiconductor materials and devices are the fundamental patents on quantum-well layer disordering and on the aluminum-based III-V oxide, now being exploited in optoelectronics (and a licensed U of I technology).

For his contributions to the field of semiconductor materials and devices, visible light-emitting diodes, diode lasers, and quantum-well heterostructure lasers, he received the IEEE’s Morris N. Liebmann Award, Jack A. Morton Award, Edison Medal, and Third Millennium Medal; John Scott Medal of the City of Philadelphia; Solid State Science and Technology Award of the Electrochemical Society; GaAs Symposium Award with Welker Medal; Monie A. Ferst Award of Sigma Xi; Charles H. Townes Award and Frederick Ives Medal (2001) of the Optical Society of America; National Academy of Sciences Award for the Industrial Application of Science; American Electronics Association 50th Anniversary Award; American Society for Engineering Education Centennial Medallion; Vladimir Karapetoff Eminent Member’s Award of Eta Kappa Nu; and John Bardeen Award of the Minerals, Metals and Materials Society.

He received the 1990 National Medal of Science, an honorary doctorate of science from Northwester University (1992), and an honorary doctor of engineering degree from Notre Dame University (1994). He is an honorary member of the Ioffe Physical Technical Institute (St. Petersburg, Russia). In 1995 he received the Japan Prize. In 1997 the Optical Society of America established the Nick Holonyak, Jr. Award; in 1998 he was elected an Eminent member of Eta Kappa Nu; and in 1999 he was elected a foreign member of the Russian Academy of Sciences. He is a member of the National Academy of Engineering, the National Academy of Sciences, and the American Academy of Arts and Sciences. Eight former graduate students are elected members of the National Academy of Engineering. In 2003 he received the Medal of Honor of the Institute of Electrical and Electronic Engineers (IEEE); Global Energy International Prize, Russia; U.S. Medal of Technology; and was elected a fellow of the American Association for the Advancement of Science. In 2004 he received the Washington Award, of the Western Society of Engineers, the Lemelson-MIT Prize of invention, the MRS Von Hipple Award; and in 2005 was named a Laureate of the Lincoln Academy of Illinois. In 2006 he became a Member of the Consumer Electronics Assn Hall of Fame, and in 2008 was inducted into the U.S. National Inventors Hall of Fame.

His research now is concerned with coupled quantum-dot/quantum-well lasers, light-emitting transistors (LETs), and transistor lasers (LTs), which has resulted in fundamental changes in transistors and in lasers.

Led-World Exclusive - LED Lamps with Remote Control


LED Lamps with Remote Control :
When it comes to choosing light globes these days, energy-conscious consumers have a multitude of choice. Both CFL bulbs and LED bulbs offer energy-efficient lighting and whilst they seem expensive at first, you realize they will save you money in the long term. However, a less appealing feature of LED globes is the bright, white light they emit, not particularly compatible with creating a warm, romantic feel in your home. That may be about to change. Sharp Corporation has just announced it has created a series of LED globes that includes a bulb with a remote-controlled, adjustable-color function and a dimmer.
The series of nine globes will be released in Japan in July. Model DL-L60 features an adjustable color function which allows users to change the light through a series of seven shades from warm white to daylight light. This model also includes a dimmer function, allowing the user to enjoy a range of color and brightness. Three other bulbs in the series are dimmer compatible, but the dimmer will need to be purchased separately.
The LED bulbs have a standard E26 screw base so will be compatible with all your existing lights and lamps. All models have a service life of approximately 40,000 hours and will not lose intensity or longevity even if continually turned on or off. With the exception of the DL-L60, users can choose bulbs with warm light or daylight white.
Warm white is described as being equal to the light from an incandescent lamp and daylight light is equivalent to bright daylight. Like other LED bulbs, they provide bright, even light and as they emit very little light in the ultraviolet range are less likely to attract insects and bugs. Prices are expected to range from ¥3880 (USD$40) to ¥7980 (USD$82).