Cellphone Gadget and Technology News » Portable Player

What are Ferrite Chokes?

admin — Sun, 20 Jun 2010 06:55:08 +0000

Ferrite beads and chokes both have impedance characteristics that can be employed as filters and safeguards to muffle unwanted interference in electronic circuits. Random high frequency signals, also know as “noise”, can cause other nearby circuits to fail to operate correctly.

An analogy for unwanted noise on top of the signal is being at a party and trying to have an intimate conversation with someone you can’t hear because everyone else around you is being too loud. In circuits, through electromagnetic coupling, a circuit that has extremely sharp pulses can induce extra signals over and above the main signal in a nearby circuit and thus becomes a source of noise, which makes it almost impossible for the receiving circuit to interpret the main signal.

So, what exactly are these things? A ferrite bead or choke is a non-resistant electronic member composed of ferromagnetic compounds that contain iron and trace amounts of nickel, zinc, or manganese oxides. The impedance properties of the ferrite choke allow it to act with a high resistance to high frequency signals and low resistance to lower frequency signals. This way, the high frequency noise is damped out and the absorbed energy is converted to a very small amount of heat. The type of ferrite material used in the bead will determine the range of frequency suppression, and the physical dimensions and shape of the ferrite bead determine the amount of suppression possible.

The beads themselves can be nothing more than a dowel-type device that has a hole in the center or something that looks like a metal blob, which is really a multi-layer bead utilized in surface mount applications. Electromagnetic Interference (EMI) suppression beads, which are comparable to inductors, are designed to rise in the transmission of signals with frequency until a resonance point. While a regular inductor’s wave propagation would begin to drop as frequency continued to increase, the ferrite bead inductance flattens out and acts as a perfect muffler for a wide frequency band.

One extremely basic use of ferrite chokes is on computer cables. You’ve probably seen these before; they look like a bump or a cylinder in the cable. These cylinders are snap-on ferrite beads that suppress the potential RF interference from the cables.

They can also be used in cell phones. There is no agreement on whether the radiation that emanates from cell phones will result in damage to one’s brain, and there are various devices being offered for sale like ferrite chokes or shields that are crafted with the intention of suppressing the radiation and the interference from the phone. If your cell phone is located anywhere near the speakers of your PC, you will actually hear this interaction of sound waves or interference.

Usually what happens is that you hear an irritating buzzing, which occurs because the cables on those speakers pick up the energy transmitted from your cell phone. Besides adding beads to your own telephone, you might also want to put snap-on-beads on your speakers to muffle the interference (unless you want the two second alarm that your phone is about to ring).

Because today’s circuits are faster and more of them are packed onto a circuit board, it is extremely desirable to employ ferrite beads and other techniques to suppress noise. Digital designers only think in terms of ones and zeros signaling until they uncover the nightmare of the sphere of analog where there is noisy circuit conduct or interference from power supplies or problems with grounding.

Besides protecting yourself from your own circuits, there are numerous “harden applications” where you need to protect the circuits and muffle any noise caused by external sources. An example would be a strong transmitter such as a cell phone accidentally being operated on a plane or a more purposeful attempt to jam a military application.

Ferrite bead and chokes are basic devices that can serve as the first line of defense for RF muffling and other noise suppressing uses. A company that produces beads can give you the arcs of impedance vs. the frequency for the beads they manufacture; typically their application engineers can assist you in choosing the correct type of bead.

4.3 Inch Widescreen Portable Media Player (DVB-T MP3 MP4 FM)

admin — Mon, 08 Mar 2010 17:08:10 +0000

Handheld multimedia system with a 4.3 inch widescreen LCD display and 8GB’s of internal memory. The CVGI-E41 also comes with a micro SD card card slot for adding additional memory, two stereo speakers and DVB-T to round out its primary feature set.

With straight and simple navigation menu system, you can instantly access all your media content within just a few seconds. To enjoy your music and videos privately, just insert the earphones into the 3.5mm jack input and listen to amazing audio output clarity. The CVGI-E41 also comes with a table kick stand, so even when your at work, you can have your multimedia station right next to your monitor while working. With a mini-USB connection it is easy to transfer files onto your new digital media player from your computer.

This is an amazing portable media unit that is perfect to take when traveling. The CVGI-E41 is built with a finely detailed molded casing and polycarb front panel to protect the inner screen, meaning it can be safely carried around in your bag or pack without having to worry about the daily wear and tear you can expect in the busy modern life.

If you are often away from home when your favorite football team is playing, then you will simply love this unit!! The CVGI-E41 is the perfect companion to keep you entertained on your journey because its intelligent DVB-T digital TV function will allow you to not miss a minute of the action. With most of Europe using DVB-T, you can enjoy crystal clear free view TV on the go.

Whats more, with the mega 8GB flash memory and additional external memory, you can use the CVGI-E41 as an ultra-convenient media storage device. The CVGI-E41 can be connected to your TV using the included AV cable so you can watch your collection of digital media files on your living rooms big screen TV.

This simple and elegant media station that is not much bigger than an iPhone is available for single and bulk purchases. Get yours today at an amazing factory direct wholesale price from the leader in wholesale electronics, Chinavasion.

At a Glance…
DVB-T 16:9 LCD Screen 8GB Internal Memory PAL/NTSC Compatibility Up to 8GB External Memory Perfect Desk and Traveling companion
Note: The DVB-T function will not work in North America, but all other function will work just great, including Videos, Music, Radio, Photo Viewing, and many more.

Manufacturers Specifications

Primary Function: Portable Multimedia Player with DVB-T Screen Size: 4.3 inch Battery: 2100 MAh Rechargeable Lithium Battery (Built In) Battery Life: up to 4 hours (depending on usage) Memory:
Internal: 8GB
External: TF/Micro SD Card Up to 8GB (not included) Audio Output: 10mW L/R Stereo EPG: Yes Resolution: 480 x 272 Screen Ratio: 4:3 / 16:9 On Board Buttons/Slots:
- Left/Right Navigation, Volume -/+ (Also acts as Up/Down Navigation), Enter, Return, ON/OFF, Power, Reset, Antenna, 3.5mm Earphone Plug-in, Mini USB Port, MIC, Speakers, TF/Micro SD Card Slot On Screen Primary Options:
- Music, DVB-T, Video, Photos, eBook, Radio, Record, File Explorer, Settings Compatible File Types:
- Music – MP3, OGG, WAV, WMA
- Video – AVI, 3GP, MPEG, RM, RMVB
- Image – JPEG, BMP, GIF
- Text – TXT DVB-T: Preferences
- Language Settings: Menu Language, Audio Language, Subtitle Language
- AV Control: Audio Output, Screen Ratio, Display Format
- Miscellaneous Settings: Display Time, OSD Transparency, Palette Color, System Status, Signal Detection (Strength / Quality)
- Preset Country Profiles: Europe (France, Spain, Austria, Belgium, Germany, Poland), China, Taiwan, Singapore [Important Note: Some countries in Europe are still launching DVB-T and may not have full coverage at this time. This product should also work in other countries such as Croatia, Denmark, Italy, Holland, Switzerland, Ukraine, U.K., Turkey, Portugal, Greece, Russia, Czech Republic. If you are not sure if your country has DVB-T then please visit Wikipedia or www.dvb.org for more information regarding the digital TV standard for your country.] FM Radio
- Frequency – 87MHz to 108MHz (Worldwide)
- Radio Recording: YES
- Quality – Low Rate, High Rate
- Preset Regions: Europe, USA, Japan, China
- Favorites MP3 Player:
- Lyric Display
- Playback Settings – All Music, Artist, Album, Genre, My Favorites Settings:
- Display Settings – Light Time, Brightness, Light Mode, Display Status
- System Settings – Upgrade, restore
- Desktop – 8 Desktop Background Images Available
- Languages
- System Information
- Auto Shut Time – 3min, 5min, 10min, 15min, 20min, NON
- TV Switch – OFF, ON
- TV Format – PAL-50, PAL-60, NTSC
- DVB Screen Size – FULL, Normal Languages: English, German, Italian, Portuguese, Holland, French, Spanish, Polish, Russian, Turkish, Cestina, Danish, Japanese, Swedish, Korean, Arabic, Greek, Traditional Chinese, Simplified Chinese Certification: CE, FCC Dimensions: L:139 x W:79 x H:17 (mm) Manufacturers Ref: S2LUCZ99K4PG

Product Notes

Large screen, comfortable, to watch videos Handheld and portable with 8GB of internal memory Connect the CVGI-E41 to your TV using the RCA cables provided Comes with a cool desktop stand, work and enjoy watching DVB-T at the same time

Package Contents

Model CVGI-E41 Digital Portable Media Player with DVB-T Earphones Kick Stand 3.5mm Jack to RCA Cable Mini USB to USB Cable Power Adapter (100-240V, 50/60Hz)

FAQ – Frequently Asked Questions

How can I navigate back to the main menu?
Just long press the return key and you will be directed back to the main menu. Will CVGI-E41 work in North America?
The DVB-T function will not work in North America, but all other function will work just great.

2.8 Inch Tft Sliding Screen Mp4 Player With Camera+game Player

admin — Tue, 19 Jan 2010 11:55:18 +0000

Here now, ePathChina introduce a very cool looking portable multimedia China MP4 Player with 2.8 Inch TFT Sliding Screen which support mp4 video, mp3 music, camera, game player, E-Book reader, calculator, SD/MMC card and other more functions.

This MP4 Player come with a 2.8 inch TFT display screen which can slide. When the screen slide up, you will see two control panel with a 4-way control pad and a 4-button control which can operate the PMP’s different functions freely. When the PMP is not in use, this sliding screen can slide down to cover the control panel, please refe to following product photo.

Built-in 1.3M Pixel CMOS digital camera, it can support the photo size as 320×240/ 640×1280/ 1280×960. And the movie playing rate is 30fps with video resolution as 320×240. With preloaded two background themes, this Portable Media Player can use any photograph option as the background as well. It also support AV out via a AV cable. The most another incredible feature is that it can be used as small game player which support many small funny games.

As a mp4 player, it support multiple audio and video format as MP3, WMA, WAV, MP4, AVI, 3GP. The internal memory of this PMP is 1GB or 2GB, and it can support SD/MMC card as it’s external memory. Via the USB cable, it can be easily connected to PC and you can handle all of your photo audio and video data file conveniently. With a built-in Rechargeable Li-ion Battery, this portable media player can be charged easily by the accessory power adapter. This MP4 Video Player also support Multi-language as English, Chinese, Korean, French, German, Spanish, Portuguese, Russian, Turkish. Others. Others, with the built in E-book / Calculator / Notepad / English to Chinese dictionary, this MP4 player can be used as a small computer and make your life more funny and efficiently.

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With a beautiful packing box, this MP4 Player come with the accessories as User Manual, Earphons, USB cable, Power adapter, AV cable, Mini CD with drive, Conversion Software + some small funny Games.

This very cool looking MP4 player, digital camera and game platform mix available at epathchina with very favourable wholesale price. Even lower prices available for you if you’re ordering in larger wholesale quantities. Get your samples first then contact us for your personal discount quotes.