Information

Frequently asked questions about LED Lights!

1. Question: What is an LED?

Answer: A light emitting diode (LED) is a semiconductor device that emits visible light when electrical current passes through it, it is a special kind of diode.

2. Question: Can LEDs be used to replace conventional incandescent and florescent light bulbs?

Answer: Yes and no. LEDs have increasingly been used in many different applications to replace old incandescent light bulbs. Examples include LED indicator lights for all kinds of electronic devices such as cellphone, calculators, automotive dash panel, LCD back-lighting, etc., LED seasonal decoration lights for Christmas and holidays, LED traffic signs and other LED direction signs, LED flashing lights, etc. Currently LEDs have limited brightness, but this is increasing as better technologies are developed to make it brighter.

3. Question: What are the advantages of LEDs compared with conventional incandescent lights?

Answer: There are many advantages that LEDs have over traditional incandescent light bulbs:

· Low power consumption: Saves you money and energy!
· Long lasting
· Cold lighting
· Ruggedness
· Small size and weight
· Simple to use

More detailed explanation about the advantages of LED lights:

LEDs are more energy efficient than incandescent bulbs. You can save money & energy by using LEDs instead of equivalent incandescent decorative bulbs.

The rated average working life of LED is 100,000 hours compared with 1,000 hours of incandescent bulbs.

LEDs emit cold lights as working LEDs generate very small amount of heat, so LEDs are much safer than equivalent incandescent light bulbs in terms of danger of fire. LEDs don’t have filaments to heat up in order to emit lights like incandescent bulbs. Lights are emitted from LEDs as a result of energy exchange occurring in the different semiconductor materials an LED is made of.

LEDs are usually shielded with solid transparent plastic materials so they are more rugged than incandescent and florescent bulbs that are usually sealed with glass.

LEDs can be powered by either AC voltage or DC voltage. The circuit that is required to appropriately drive LEDs is much simpler than that for florescent bulbs.

4. Question: What are the disadvantages of LEDs compared with incandescent or florescent bulbs?

Answer: LEDs emit limited amount of lights at a relatively small angle range, while incandescent and florescent light bulbs illuminate in all directions.

LEDs are more expensive than equivalent incandescent light bulbs. This is why some customers still hesitate to buy LED products even though LEDs have so many obvious advantages over incandescent bulbs and people actually can save money by using LED products in the long run.

5. Question: How do the LED light strings and incandescent light strings in terms of reliability?

Answer: LEDs are more reliable. However, in the case of light burning, an incandescent light bulb will always burn open, namely, the filament of the incandescent bulb breaks, so the whole string will always fail, while an LED light may either burn open like an incandescent light bulb or burn short where a short circuit is formed inside the LED, so the burned out LED will stop lighting, but all the rest LEDs in the string still light normally. And LEDs usually burn short, therefore, LEDs are more reliable than incandescent light bulbs.

6. Question: Why are LEDs of some colors are more expensive than LEDs of other colors?

Answer: Different semiconductor materials are used for different color LEDs, and some semiconductor materials are more expensive than others. Also manufacturing costs are different for different colors. For example: White LEDs are the most expensive because red, green and blue LEDs are combined together to make a white LED.

Sources of interference

Since natural interference phenomena do not really affect the modern equipment, the actual problems today are generated accidentally by the actual operation of the equipment. Basically, the radiated interfering signals are classified in a narrow band and broad band. Narrow band signals occupy a small portion of the radio spectrum and have the energy concentrated in a single frequency wave. However, when modulation is introduced, the narrow band signal may generate side bands of energy which may cover hundreds of kilohertz. Examples of sources for narrow band signals are radio & TV transmitters, radio transceivers, cellular telephonic equipment and Doppler radar. These sources start out with very low harmonic frequency outputs but can cause harmonic frequencies to be generated if they are used in areas which can present non-linear conditions to the RF energy through secondary transmission of these signals.

Broad band signals are those whose energy is spread over tens of hundreds of Megahertz. They are generated by narrow pulses with sharp rise times, characteristic of radars, gas discharge tubes, engine ignition systems, power line discharges, computer clocking pulses, motor brushes and switching regulators. The steepness of the pulses causes problems because the short rise times mean very high frequencies and that which may appear to be a low impedance can actually have a high inductive component and be a high impedance for the rise time.

Oscillator circuits on printed circuit boards can cause energy to be both conducted and radiated. These oscillator sources may be part of the power supply (as in switching regulators) or they may be part of the logic clock circuits. Other source of radiation could be amplifier circuits with a high slew rate, which can have very fast rise times and, if not terminated properly, can cause a large spectrum of noise. Actually, every frequency source could be a potential source of interference and all interference signals can be coupled to the power line and conducted to the power mains, thus creating problems to other equipments connected close to the signal source

Using ferrite cores for EMI suppression
Based on the specific magnetic properties of the Nickel-Zinc ceramic ferrite materials, molded cores, when used as EMI filters, absorb the energy of the high frequency noise on the line and dissipate it as quantities of heat. Since the electrical resistance component of the material is reduced at low levels of frequency, the ferrite cores provide very low series impedance and do not affect the normal data signals on the line.

Cut the end of the cable off square with a set of wire cutters. Place the coax in a stripper tool, with the end flush against the side of the tool. (separate stripper is available here on our site.) Twirl the strip tool 360 degrees in both directions around the cable until the "crunching" stops. (5 to 10 turns.)

Remove the strip tool and pull off the stripped material. Fold back the remaining braid so that there is only one layer of foil left against the center white dielectric. Note that with quad shield cable, there may be two layers of braid and one layer of foil to remove. When using our stripper, adjust the blade so that it cuts through the outer layer of braid and foil. This makes the crimping operation much quicker and easier. If you do not get everything except the innermost layer of foil removed, it may be very difficult to push on the connector.

Insert the cable into the Perma-Seal connector. When inserted properly, the white insulator of the cable should be flush with the metal flange. you can see this action by looking into the connector at the threaded end. If you cannot get the coax to go in all the way, pull it out and push it in again. Sometimes the cable catches on the inner ring or the braid catches. If the cable jacket is loose, you may need to kink the cable slightly in your palm while pressing it into the connector (no more than 45 degrees).

Lay the cable-connector assembly into the crimp tool. Squeeze the handle until the top ring seats all the way into the connector. You should hear or feel a "click" as it pops into position. Remove the coax and connector from the crimper. Test the crimp by giving the cable a nice "tug", all should be fine. If not the tool may need some minor adjustments or the braid may have prevented the connector from seating properly. FYI, YOU CANNOT REUSE THE CONNECTOR. You will need to try another if the cable pulls out.

Comparison between CAT5, CAT5e, CAT6

In the context of the 100-ohm UTP (Unshielded Twisted Pair) type of cable used for Ethernet wiring the only categories of interest are Cat3, Cat4, Cat5, Cat5e, Cat6. CATx is an abbreviation for the category number that defines the performance of building telecommunications cabling as outlined by the Electronic Industries Association (EIA) standards. Some specifications for these categories are shown further down.

Up until the late 1980s thick or thin coaxial cable was typically used for 10-Mbps Ethernet networks, but around that time, UTP cabling became more commonly used because it was easier to install and less expensive. UTP CAT3 and CAT4 were used for a quite limited time since the emergence of 100Base-TX networks meant a quick shift to CAT5. By the year 2000, moves to gigabit (1000Base-TX) Ethernet LANs created a need for another specification, CAT5e. CAT5e is now being superseded by CAT6 cable.

If you're cabling a mission critical system or you want your network to be future proof, go for the CAT6 cables (and patch panels and connectors), but for the average home or small office network CAT5 or CAT5e will be just fine.

Crossover Cables vs Straight Through Cables

Ethernet patch cables can be wired in three different ways, the two main ways are called straight through and crossover. The third type is called rolled and has only specialized applications.

Generally speaking, straight through cables are used to patch between different types of equipment; for example, PCs to a hub.
Conversely, crossover cables are generally used to patch between similar types of equipment; a PC to another PC for example. Some modern hubs don't care if you use crossover cables or straight through cables, they work out what you're using and configure themselves accordingly.

As stated at the outset, the actual difference is in the wiring. Inside the UTP patch cable there are 8 physical wires although the network only uses 4 of them (the other 4 are simply wasted). The 8 wires are arranged in what's known as pairs and one pair is used to send information whilst the other pair is used to receive information.

On a PC, the pair on pins 1 and 2 of the connector send information, whilst the pair on pins 3 and 6 receive the information. To make PCs talk to each we therefore need to connect the send pair of one PC to the receive pair of the other PC (and vice-a-versa). That means we need a crossover cable. If we used a straight through cable the both be listening on the one pair - and hearing nothing, and sending on the one pair - achieving nothing.

The Restriction of Hazardous Substance the European Union's Directive
2002/95/EC . This Directive will lawfully prohibit placing new electrical
and electronic components, equipment and other usages containing more than
levels of lead, cadmium, mercury, hexavalent chromium, polybrominated
biphenyl and polybrominated biphenyl ether (PBDE) into the European
Union from 1 July 2006.

Wired Communications is a proud supporter of the RoHS Directive as well as
several other environmental initiatives being enacted globally to reduce the
effects of hazardous substances used in the production of electrical and
electronic products that maybe potentially harming the environment. We are
actively implementing processes and procedures to control and eliminate the
use of the directive's restricted substances in all products that are
manufactured from our sources.
In October 2005 we have also the ISO-14001 Environmental Management System
to further our dedication to both our local and global environment.

LEAD is mostly used and thus requiring the most attention. This is also the
case for the entire electronics industry. Any cable sold with the RoHS
qualification should be manufactured as such: Lead - Significant use in
terminal finish for connectors/components, PWB board finish and solder for
PWB assembly; use as UV/heat stabilizer in PVC cable jackets. Mercury - Not
used. Cadmium - Very limited use as colorant for plastic materials.
Hexavalent Chromium - Limited use as corrosion protection for retention
hardware (e.g. screws, washers); limited use as conversion coating for
metallic housings. PBB - Very limited use as flame retardant in plastic
materials.
PBDE - Very limited use as flame retardant in plastic materials. (These
statements and the information contained in this document do not constitute
a warranty of quality nor regulatory compliance of any product. The
information is strictly based on information obtained by Wiredco at the time
this document was published.)

HDCP stands for High-Bandwidth Digital Content Protection, a copy protection scheme to eliminate the possibility of intercepting digital data midstream between the source to the display. The format designed by Intel and licensed by Digital Content Protection, LLC using an authentication and key exchange procedure before video and audio is presented. Products compatible with the HDCP scheme such as DVD players, satellite and cable HDTV set-top-boxes, as well as few entertainment PCs requires a secure connection to a compliant display, the process often described as the handshake. Due to the increase in manufacturers employing HDCP in their equipment, it is highly recommended that any HDTV you purchase is compatible. Although most video devices support high-definition video over component output, analog connections are scheduled to phase out in the future or possibly forced to limited resolutions output.

Why is it important to me?

Although manufacturers are still making most products with at least component HD output, new generation of products like HD-DVD and Blu-Ray devices will limit the analog output resolution (Analog defined as Component or RGBHV). The highest resolutions these devices can output (720p/1080i/1080p) will be available on via the digital (DVI or HDMI) connections that employ HDCP encryption. Any new HDTV purchase should have a digital HDCP compatible input.
It is important to note that HDCP is currently not a standard used in PC monitors, and almost none of these displays have Component inputs. Although PC monitors are HDTV capable, HDCP encryption limits this type of use. If you use an HTPC and want to ensure dual use of your new flat panel display, look for HDCP compatibility.

How does it work?

A simple answer is that an HDCP session will result in the exchange of keys between the source and display device. The source device will query the display to make sure that the equipment is HDCP compliant before video is shown. Non-HDCP devices such as PC's and older model DVI products will work with any DVI compliant display, but the HDCP compliant boxes will show an image only on HDCP compliant display.

Other products affected by HDCP are scalers, switchers, and splitters (distribution amps). While these devices do no authentication for key exchange, they must be able to transmit the presence of HDCP if the video is handled (processed) in any way. Due to the two different formats of digital connections, occasional inability for proper communications may result in loss of interoperability. The newer format, HDMI was designed to be backwards compatible with DVI and in most instances, the two signal types are easily adaptable, but older devices may not always work well with in-line devices like scalers or switchers. These problems can sometimes be fixed in "firmware' although that is not always the case. Incompatibility is often displays on-screen as a snowy image or an error message.