Tuesday, December 17, 2013
Protection For Telephone Line Circuit
A long time ago when telephones were so simple almost nothing could go amiss from an electrical point of view, Telecom operators installed surge protection on all telephone lines exposed to storm risks. Paradoxically, now that we are hooking up delicate and expensive equipment such as telephones filled with electronics, fax machines, (A)DSL modems, etc., this protection has disappeared.
However, if you have the good fortune to live in the countryside in a building served by overhead telephone lines, there’s an obvious risk of very high voltages being induced on the lines during thunderstorms. While we have lost count today of all of the modems, fax machines and other telephones that have been destroyed by a ‘bolt of lightning’, surprisingly you only have to invest a few pounds to get a remarkably efficient protection device like the one we are proposing here.
During a storm, often with lightning striking near a telephone line, the line carries transient voltages up to several thousands of volts. Contrary to the HV section of television sets or electrical fences, on which practically no current is running, in the case of lighting striking current surges of thousand of amps are not uncommon. To protect oneself from such destructive pulses, traditional components are not powerful or fast enough.
As you can see on our drawing, a (gas-filled) spark gap should be used. Such a component contains three electrodes, insulated from each other, in an airtight cylinder filled with rare gas. As long as the voltage present between the electrodes is below a certain threshold, the spark gap remains perfectly passive and presents an impedance of several hundreds of MW. On the other hand, when the voltage rises above this threshold, the gas is very rapidly ionized and the spark-gap suddenly becomes a full conductor to the point of being able to absorb colossal currents without being destroyed.
Protection Circuit Diagram For Telephone Line :
The one we are using here, whose size is of the same magnitude as an ordinary one watt resistor, can absorb a standardized 5,000 amps pulse lasting 8/20 ms! Since we are utilizing a three-electrode spark gap, the voltage between the two wires of the line or between any wire and ground, cannot exceed the sparking voltage, which is about 250 volts here. Such protection could theoretically suffice but we preferred to add a second security device made with a VDR (GeMOV or SiOV depending on the manufacturer), which also limits the voltage between line wires to a maximum of 250 volts.
Even if this value seems high to you, we should remember that all of the authorized telephone equipment, carrying the CE mark must be able to withstand it without damage. This is not always the case however with some low-end devices made in China, but that’s an entirely different problem. Since pulses generated by lightning are very brief, the ground connection of our assembly must be as low-inductance as possible.
It must therefore be short, and composed of heavy-duty wire (1.5 mm2 c.s.a. is the minimum). If not, the coil, composed of the ground connection, blocks the high frequency signal that constitutes the pulse and reduces the assembly’s effectiveness to nothing. Finally, please note that this device obviously has no effect on the low frequency signals of telephones and fax machines and it does not disturb (A)DSL signals either.
Author: Christian Tavernier - Copyright: Elektor Electronics Magazine
Build Motorcycle Alarm Circuit Diagram
This is a Motorcycle Alarm Circuit Diagram. Any number of normally open switches may be used. Fit the mercury switches so that they close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its center-stand. Use micro-switches to protect removable panels and the lids of panniers etc. While at least one switch remains closed, the siren will sound.
Motorcycle Alarm Circuit Diagram
About tw1o minutes after the switches have been opened again, the alarm will reset. How long it takes to switch off depends on the characteristics of the actual components used. But, up to a point, you can adjust the time to suit your requirements by changing the value of C1.The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction.Without its terminal blocks, the board is small. Ideally, you should try to find a siren with enough spare space inside to accommodate it. Fit a 1-amp in-line fuse close to the power source.
This protects the wiring. Instead of using a key-switch you can use a hidden switch; or you could use the normally closed contacts of a small relay. Wire the relay coil so that it is energized while the ignition is on. Then every time you turn the ignition off, the alarm will set itself.When it`s not sounding, the circuit uses virtually no current. This should make it useful in other circumstances. For example, powered by dry batteries and with the relay and siren voltages to suit, it could be fitted inside a computer or any thing else that`s in danger of being picked up and carried away. The low standby current and automatic reset means that for this sort of application an external on/off switch may not be necessary.
cell phone jammer will not intercept on the base station
cell phone jammer will not intercept on the base station.
Visible, smart phones, large screen, large screen products favored by the users. Chinese mobile phone market in June 2011, the smart phone market with different screen sizes attention to the proportion of contrast. Case Study: Apples share of continued expansion. Apples global handset market share continued to expand. According to the U.S. market research firm Gartner statistics show that, since 2007, Apple introduced the iPhone smart phone, smart phone market, the pattern began to change. In 2008, Apple alone an iPhone, the global market share has reached 8.2 percent, while the first quarter of 2011, only three years, alone, four generations of iPhone products, Apples market share has reached 16.8%, to become the worlds first The three operating systems. cell phone jammer will just influence the downlink.
2007-2011Q1 Apple Worldwide sales of mobile phones and smart phone market share trend. Data sources Gartner, data management: ZDC. Apple user attention in the smart phone market in China is climbing. Rattling trend in the global mobile phone market with Apple, the Apple in the smartphone market, but also showed the fierce attacks, especially in cooperation with China Unicom, Apple users attention from record highs. The ZDC monitoring data show that the smart phone market in China in June 2011, Apple accounted for 9.2 percent of the concern proportion, only a difference of 2.6 percent and Motorola. In addition, from Apple released the data, the establishment of the ecosystem and no brand. This is a considerate design for cell phone jammer .
Since 2011, the three operators for 3G mobile terminals, a number of Central Purchasing universal low-priced products has always been an important source of new 3G subscribers, new subscribers expected to reach the end of universal terminal undoubtedly become the focus of the tender object, and an important platform to promote value-added services as operators necessary to support the role of popular intelligent terminal to enhance 3G users overall ARPU value are bound to become the top priority of purchases and sales. Sino Market monitoring data show that in October this year, 3G smart market 700 to 1500 the proportion of the price reached 54.7%, 24.6% increase compared to same period last year, up significantly. The insulation feature of cell phone jammer is very important for the customer.Products, the number of 3G thousands of intelligent machines models increase from 15 in October 2010 to October 2011, 123 models, thousands of intelligent machines has become a new force of the smart phone market. The low-end market into focus. IPhone users and thousands of intelligent machines the user using the data flow to compare, you can find iPhone users monthly data traffic is not significantly higher.
Continue Reading[..]
Visible, smart phones, large screen, large screen products favored by the users. Chinese mobile phone market in June 2011, the smart phone market with different screen sizes attention to the proportion of contrast. Case Study: Apples share of continued expansion. Apples global handset market share continued to expand. According to the U.S. market research firm Gartner statistics show that, since 2007, Apple introduced the iPhone smart phone, smart phone market, the pattern began to change. In 2008, Apple alone an iPhone, the global market share has reached 8.2 percent, while the first quarter of 2011, only three years, alone, four generations of iPhone products, Apples market share has reached 16.8%, to become the worlds first The three operating systems. cell phone jammer will just influence the downlink.
2007-2011Q1 Apple Worldwide sales of mobile phones and smart phone market share trend. Data sources Gartner, data management: ZDC. Apple user attention in the smart phone market in China is climbing. Rattling trend in the global mobile phone market with Apple, the Apple in the smartphone market, but also showed the fierce attacks, especially in cooperation with China Unicom, Apple users attention from record highs. The ZDC monitoring data show that the smart phone market in China in June 2011, Apple accounted for 9.2 percent of the concern proportion, only a difference of 2.6 percent and Motorola. In addition, from Apple released the data, the establishment of the ecosystem and no brand. This is a considerate design for cell phone jammer .
Since 2011, the three operators for 3G mobile terminals, a number of Central Purchasing universal low-priced products has always been an important source of new 3G subscribers, new subscribers expected to reach the end of universal terminal undoubtedly become the focus of the tender object, and an important platform to promote value-added services as operators necessary to support the role of popular intelligent terminal to enhance 3G users overall ARPU value are bound to become the top priority of purchases and sales. Sino Market monitoring data show that in October this year, 3G smart market 700 to 1500 the proportion of the price reached 54.7%, 24.6% increase compared to same period last year, up significantly. The insulation feature of cell phone jammer is very important for the customer.Products, the number of 3G thousands of intelligent machines models increase from 15 in October 2010 to October 2011, 123 models, thousands of intelligent machines has become a new force of the smart phone market. The low-end market into focus. IPhone users and thousands of intelligent machines the user using the data flow to compare, you can find iPhone users monthly data traffic is not significantly higher.
Wednesday, June 12, 2013
ISL97672A power LED driver electronic project and circuits
Using the ISL97672A can be designed a power LED driver circuit that controls six channels of LED current for LCD backlight applications. The ISL97672A power LED driver is capable of driving LEDs from 4.5V to 26.5V, with a maximum output of 45V.
The ISL97672A power LED driver employs an adaptive boost switching architecture that allows Direct PWM dimming with linearity as low as 0.007% at 200Hz or 0.8% at 20kHz. Dimming can be as high as 30kHz.
This LED driver can compensate for non-uniformity of forward voltage drops in the LED strings. Its headroom control circuit monitors the highest LED forward voltage string for output regulation to minimize voltage headroom and power loss in a typical multi-string operation.
The IC features extensive protection functions that flag whenever a fault occurs. The protections include string-open and short-circuit detections, OVP, OTP, and an optional output short-circuit protection with a fault disconnect switch
LED drivers for direct, multiplexed videowalls, information displays circuits
Will The Next Generation Iphone Be Called Iphone 4s
According to a Web site message, the next generation iPhone may not be the iPhone 5, but may be named the iPhone 4S; If you really gone this route, it should be in terms of exterior design with the iPhone 3G to the iPhone 3GS, so nothing much has changed, while in the inner part, they will use the same series with the iPad 2 Apple A5 dual-core processor, but the photography is not whats heard of the Great Leap Forward features, the legendary eight megapixels, and will not appear with 1080p video, but still is five megapixels with 720p video, good news is that pre-video photography will be with the main camera module, like that time might have a 720p video.
And although the appearance will look almost exactly the same, but the actual screen size, resolution is not clear; operating systems, WWDC will see the iOS 5 above preview, iOS 5 of the official launch date may not be too fast; OS shipped with the iPhone 4S still iOS 4.x, where the fork is still unclear, but the time will be published in September, when the time is listed along with black and white; As all this is true or not, we just only wait for other official news!
Continue Reading[..]
And although the appearance will look almost exactly the same, but the actual screen size, resolution is not clear; operating systems, WWDC will see the iOS 5 above preview, iOS 5 of the official launch date may not be too fast; OS shipped with the iPhone 4S still iOS 4.x, where the fork is still unclear, but the time will be published in September, when the time is listed along with black and white; As all this is true or not, we just only wait for other official news!
Wednesday, June 5, 2013
2005 Mitsubishi Lancer Wiring Diagram Electrical System
Get The Detail Car Stereo Wiring Harness Catalog Here Free.
Keywords Starter Wiring Diagram Diagram Motorcycle Car Starter Circuit.
Jeep Grand Cherokee Radio Adaptor Wiring Harness Circuit Schematic.
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2005 Mitsubishi Lancer Evo Ix Wiring Diagram Electrical System.
Cassette Cd And 6 Speakers Audio System Wiring Circuit Schematic.
Peugeot 206 Wiring Diagram For Central Door Locking Circuit.
About Volvo 960 Electrical System And Wiring Diagram 1992 Here.
Find More Information About 2002 Bajaj Legend Wiring Diagram Here.
Tuesday, June 4, 2013
Crossover Cable Source Destination Wires
Limited Ethernet Wiring Diagrams Patch Cables Crossover Cables.
Connectlink Wireless Ethernet Wiring Diagram.
Ethernet 10 100 Mbit Cat 5 Network Cable Wiring Pinout And Wiring.
Tech Info Lan Wiring And Pinouts.
Ethernet Cable Connection Between The Dsl Modem And The Netgear Hub.
Cat7 Cables 100 Ohm Utp Unshielded Twisted Pair Ethernet Wiring.
With A Crossover Cable The Source And Destination Of The Utp Wires.
Known As 568b Is The Most Common Arrangement For Ethernet Cable.
Cat 5 Ethernet Cable Standards Pin Out Assignments.
Ethernet Straight Through Cable Pin Configuration.
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