Video conferencing is an idealized way of 21st century communication, using the latest high-tech equipment connected to the network for remote projects, and face-to-face meetings to achieve the same effect, and will not create waste of resources. In order for this technique to be best practice, essential to understand how to optimize the quality of video conference.

Step one: start with software

Optimized video of JVC BN-VF823 Battery Charger  the meeting, the first step is to choose the quality of professional video conferencing software. Free chat software such as Skype and GoogleChat aside aside, software should be removed from the video and the audio is smooth and clear perspective to choose.

Today, the four professional video conferencing software under industry praise, they are AdobeConnect,CiscoWebExMeetingCenter,FuzeMeetingPro and CitrixGoToMeeting. In the field of video conferencing, they are not the most professional, but their pursuit of ease of use, and allows a large number of participants to attend the meeting at once. In addition, with most of the major platforms, including Windows and Mac platform, seamlessly.

In addition, short-term rental video conference rooms or spend hundreds of thousands of dollars to install video conferencing system, which will significantly improve the quality of video conference.

Second step: start with the camera

Even with the best software, if you use a low resolution camera will cause a reduction in audio and video quality. Select a higher resolution camera than money spent on professional video conferencing systems and practical.

Select a video conference camera, its basic configuration requires at least 1280*720 pixel resolution and 30 frames per second, such as Panasonic Lumix DMC-FS18 Battery Charger  a EverymanHD FREETALK. In addition to video cameras, select the digital camera is also good, they provide clearer, faster image, and you can set up a tripod. For a large group, or even wants to have more than one digital video camera.

Before you start a video conference, check camera angles to ensure that everyone within the camera. Note to avoid background plate shaking and other interference. Select a design simple, solid color background is a good method.

Third step: starting with lighting

Video captures one of the important aspects of quality depending on the lighting effects. If the light in the room is not sufficient, images are sent to the remote will fall short of the standards. Light is good is not difficult, just the lights of the room on the list.

In addition, to ensure that no more than Outlook brightness background lighting, never use the light from the computer on the monitor as the primary light source. You can choose to open the Dome light, but you want to get better results, try to avoid lighting the objects.

The fourth step: starting with sound effects

Finally, in order to ensure that participants can clearly hear the sound, the video quality of the Conference should further optimize. Nikon Coolpix S50C Battery Charger  Clear sound in the video conferencing and video quality is equally important, and only through the camera's built-in microphone is easy to achieve.

This does not mean that, participants will need to bring a headset and a microphone to communicate audio information. Faceted clear desktop microphone to capture everyone in the room sound. Wireless microphones, is a simple, cheap choice, will significantly improve the sound quality, so attendees don't have to because the sound is not clear and missed content troubles.

Fifth step: starting with the bandwidth

If Internet connection can't handle streaming high definition video and sound, and that these improvements are equal to zero.

Today's society, I think every family will have their own digital camera, whether to travel, the art of shooting, will bring great convenience, perhaps we have some understanding of the digital camera, for example, exposure, coke, the photosensitive values ??are interoperable regardless of which brand of camera, then how can shoot photos with the technical content? How can I make the pictures are more standards? The following I will introduce you to the following digital camera a few shooting tips to keep your shooting skills by leaps and bounds

 1, digital cameras, shooting techniques in portrait mode

Usage: This mode is mainly used to shoot photos of the characters, such as a passport. The digital camera will aperture to the maximum,  Nikon D70S Battery Charger ake a shallow depth of field effect. Some cameras will be able to demonstrate the effect of stronger color tone, contrast or soften the effect of shooting in order to highlight the portrait subject.

Tip: In this shooting situations, we only need to pay attention to issues such as framing and composition. If you use flash when shooting indoors should open a digital camera red-eye reduction function. Addition should be kept some distance between the camera and the target, the best in the zoom function of the distance and then zoom (Zoom) closer to the target shooting

 2, digital camera shooting techniques in landscape mode

 Purposes: to shoot scenic, digital camera will iris to minimum in order to increase the depth of field, another focus into infinity, so the photos to get the most clear effect.

skills: attention to the little, we only need to pay attention to environmental light, for example, do not let direct sunlight lens. Sunset and environment may want to manually adjust the white balance. 

3, panorama mode for digital camera tips

 Purpose: shooting ultra-wide range of screen (such as mountains, the sea), a digital camera each photo to stay the extra position to help the photographer for shooting more than Zhang Fengjing photos, and then form an extra-wide landscapes.

Skills: required when shooting some of the more obvious (such as buildings) as the convergence of the mark, so that shoot the next photo easier to combine. Recommend using a tripod to ensure that the picture is stable and accurate alignment.

4, night mode of the digital camera tips

Purposes: Night mode in general, there are two, the former use about 1/10 second shutter shooting, which may result in underexposed. While the latter a few seconds long shutter exposure time, to ensure that the photos full exposure, photo screen will pnasonic SDR-H80 Battery Charger e brighter. These two smaller aperture to shoot at the same time the flash will be shut down.

Techniques: first, shooting night scenes should be using a tripod; In addition, it is best to use the Timer delay mode to trigger the shutter if the hand may move to the camera.

5, digital cameras, shooting techniques, Night Portrait mode

Purposes: in the night taking pictures of people (such as visiting the Lantern Festival), digital cameras usually use a few seconds to about 1/10 second shutter shooting distant scenes, and use the flash to illuminate the prospects of the main characters, usually the flash in flash to close The former is triggered.

Techniques: we had better use a tripod, another note of the distance between the target and flash, to avoid the emergence of the foreground object is too bright.

6, digital cameras, shooting techniques, lighting mode

Usage: This mode is similar to night mode, the shutter will be closed in a few seconds to get enough exposure (like a film camera B gate)
.

 Skills: shooting techniques, and night modes.

 7, Backlight mode of the digital camera skills

Uses: In some backlight environment, a strong light behind the subject. Camera to enhance the accuracy of the exposure-weighted metering, and increase the EV value in order to avoid the subject is too dark, some cameras will also use the flash fill light.

Skills: should first focus on the subject and press the shutter halfway and hold then move the camera to other parts of the composition. The photographer should pay attention to the light source, if they are too strong light, and should change the location shooting.

8, the dynamic model of digital camera techniques

Shutter speed of purposes: to fast-moving objects, digital cameras will be transferred faster (1/500 seconds), or raise the ISO sensitivity to value.

Tip: when shooting low light, may not be able to lock the high-speed moving images, so it is best to use this mode in the sun.

9, the digital camera macro mode shooting techniques

Uses: used to shoot a small target such as flowers, insects, etc., and digital cameras will use a "macro" focal length, and turn off the flash.

Skills: Macro mode, the distance between the target and digital cameras a minimum shooting distance (4cm) should be indicated in the camera manual macro, otherwise they will be unable to focus. And we should also note that the light source, can not make the target too dark, it is best to use a tripod to shoot.

The skills of more than nine digital cameras are very easy to understand, as long as nine shooting skills can be trained to master the above, I believe that you photograph the level will be a qualitative leap, not the amount of breakthrough do not know each times taking pictures when the will does not have a feeling that the pictures are not what you want, think how to  JVC BN-V408U Battery Charger hoot do not have very good results, now we learn shooting techniques 9, I believe everyone shot level increased dramatically, oh.

Today's society, I think every family will have their own digital camera, whether to travel, the art of shooting, will bring great convenience, perhaps we have some understanding of the digital camera, for example, exposure, coke, the photosensitive values ??are interoperable regardless of which brand of camera, then how can shoot photos with the technical content? How can I make the pictures are more standards? The following I will introduce you to the following digital camera a few shooting tips to keep your shooting skills by leaps and bounds

 1, digital cameras, shooting techniques in portrait mode

Usage: This mode is mainly used to shoot photos of the characters, such as a passport. The digital camera will aperture to the maximum,  Nikon D70S Battery Charger ake a shallow depth of field effect. Some cameras will be able to demonstrate the effect of stronger color tone, contrast or soften the effect of shooting in order to highlight the portrait subject.

Tip: In this shooting situations, we only need to pay attention to issues such as framing and composition. If you use flash when shooting indoors should open a digital camera red-eye reduction function. Addition should be kept some distance between the camera and the target, the best in the zoom function of the distance and then zoom (Zoom) closer to the target shooting

 2, digital camera shooting techniques in landscape mode

 Purposes: to shoot scenic, digital camera will iris to minimum in order to increase the depth of field, another focus into infinity, so the photos to get the most clear effect.

skills: attention to the little, we only need to pay attention to environmental light, for example, do not let direct sunlight lens. Sunset and environment may want to manually adjust the white balance. 

3, panorama mode for digital camera tips

 Purpose: shooting ultra-wide range of screen (such as mountains, the sea), a digital camera each photo to stay the extra position to help the photographer for shooting more than Zhang Fengjing photos, and then form an extra-wide landscapes.

Skills: required when shooting some of the more obvious (such as buildings) as the convergence of the mark, so that shoot the next photo easier to combine. Recommend using a tripod to ensure that the picture is stable and accurate alignment.

4, night mode of the digital camera tips

Purposes: Night mode in general, there are two, the former use about 1/10 second shutter shooting, which may result in underexposed. While the latter a few seconds long shutter exposure time, to ensure that the photos full exposure, photo screen will pnasonic SDR-H80 Battery Charger e brighter. These two smaller aperture to shoot at the same time the flash will be shut down.

Techniques: first, shooting night scenes should be using a tripod; In addition, it is best to use the Timer delay mode to trigger the shutter if the hand may move to the camera.

5, digital cameras, shooting techniques, Night Portrait mode

Purposes: in the night taking pictures of people (such as visiting the Lantern Festival), digital cameras usually use a few seconds to about 1/10 second shutter shooting distant scenes, and use the flash to illuminate the prospects of the main characters, usually the flash in flash to close The former is triggered.

Techniques: we had better use a tripod, another note of the distance between the target and flash, to avoid the emergence of the foreground object is too bright.

6, digital cameras, shooting techniques, lighting mode

Usage: This mode is similar to night mode, the shutter will be closed in a few seconds to get enough exposure (like a film camera B gate)
.

 Skills: shooting techniques, and night modes.

 7, Backlight mode of the digital camera skills

Uses: In some backlight environment, a strong light behind the subject. Camera to enhance the accuracy of the exposure-weighted metering, and increase the EV value in order to avoid the subject is too dark, some cameras will also use the flash fill light.

Skills: should first focus on the subject and press the shutter halfway and hold then move the camera to other parts of the composition. The photographer should pay attention to the light source, if they are too strong light, and should change the location shooting.

8, the dynamic model of digital camera techniques

Shutter speed of purposes: to fast-moving objects, digital cameras will be transferred faster (1/500 seconds), or raise the ISO sensitivity to value.

Tip: when shooting low light, may not be able to lock the high-speed moving images, so it is best to use this mode in the sun.

9, the digital camera macro mode shooting techniques

Uses: used to shoot a small target such as flowers, insects, etc., and digital cameras will use a "macro" focal length, and turn off the flash.

Skills: Macro mode, the distance between the target and digital cameras a minimum shooting distance (4cm) should be indicated in the camera manual macro, otherwise they will be unable to focus. And we should also note that the light source, can not make the target too dark, it is best to use a tripod to shoot.

The skills of more than nine digital cameras are very easy to understand, as long as nine shooting skills can be trained to master the above, I believe that you photograph the level will be a qualitative leap, not the amount of breakthrough do not know each times taking pictures when the will does not have a feeling that the pictures are not what you want, think how to  JVC BN-V408U Battery Charger hoot do not have very good results, now we learn shooting techniques 9, I believe everyone shot level increased dramatically, oh.

The digital camera is a highly sophisticated electronic products, improper use and its own defects will cause a malfunction. Here to talk about the various failures of the digital camera and approach.

A.

Fault phenomenon: LCD display image distortion, color cast, blur, chaos, and even black. Photographs and video are so. Common digital camera for a few years ago. The most frequent of such failure, I have encountered the CANON the A70, the A75, S1 IS; the SONY F717; NIKON 5700 and other models such failure.

The cause of the malfunction: CCD problem. All the common features of these failures camera with a SONY issue of CCD, the CCD internal lead JVC BN-VG107 Battery Charger wire sealing off the lead to failure after a long time.

The solution: go directly to the aftermarket. Such failures is a free maintenance. Each manufacturer has failed camera list, you can look up the Internet their own camera is in the list, in the words of maintenance free. Not in the list within the camera to be repaired would have his own pocket.

The method of repair is to replace the CCD, as if some of the maintenance department can be failure on the CCD glass package removed, lead to re-welded and then sealed back.

Two.

Fault phenomenon: the photo covered with stripes and overexposed, normal camera.

Fault: shutter damage, has been open and not closed. Or shutter cable is bad.

Solution: Check the shutter components and cable, general damage to the cable.

Such failure to Samsung's camera is the most frequent, do not believe we BAIDU "stripes" to know. Samsung almost all of the camera may be the occurrence of such failure, because the shutter component cable is broken. I do not understand, Samsung you will not be another good quality cable, and the problems a few years do not change, even the blues series have this problem, speechless.

For these failures, the Samsung official said that the free maintenance, but in some places, may be the maintenance necessary to spend money. Recommended that such a failure occurs friends take on the Samsung camera to the sale to ask, free maintenance is best, but if you want to charge, we can argue, it is not loaded into Lanzi bitch downtown a downtown, and sometimes receive that think of the effect.

3.

Fault phenomenon: normal indoor shooting, outdoor overexposed

The cause of the malfunction: aperture components damaged, or the cable is bad

The solution: replace the corresponding parts

4.

Fault phenomenon: the operation of the camera as usual, but the viewfinder and take a picture all black

Fault detection and reason: the camera to look at, to see the shutter button is pressed to the moment the shutter is closed and then open. If the shutter opening and closing, typically a CCD or the motherboard. If the shutter action is the shutter failure, the shutter has been closed can not be opened.

Fault solution: replace or repair the corresponding component.
 

5

Fault phenomenon: the camera is turned abnormal sound, the lens can not be extended or retracted, the error message is displayed on the LCD screen. Prone to general camera overboard

Fault: The lens internal mechanical parts of stuck.

The solution: open the camera to check inside the lens. Vary in the severity of such failure. Lucky rails dislocation of the words may be the lens, remove the installed Haojiu Hang up. The bad luck if you broke something inside the camera gear, may be that the camera scrapped.

Friendly reminder: Do not external force on the camera lens, especially the boot off.
 
6.

Fault phenomenon: does not boot

Failure reasons: more complicated. Replace the battery to boot that would be reflected not, motherboard problem, first check the power supply circuit on the motherboard.

The solution: found fault corresponds to resolve.

I used to repair a card machine does not boot, the battery contacts sealing off. There is also a camera power button damage.

7.

Trouble phenomenon: unable to focus, the photographs are all fuzzy

Fault: Focus component failure, the focus motor cable is broken, it could be the lens fell a knock, so that the inside of the lens shift.

The solution: found fault corresponds to resolve. If the lens shift can be corrected with a 502 stick.

8.

Fault phenomenon: the flash damage

Troubleshooting: If the flash is not itself generally not bad. Check the motherboard on the circuit. Check flash oscillator circuit, JVC GR-DVL317U Battery Charger the flash capacitor and trigger circuit. The general cause of the malfunction unsoldering and some components (transistors, etc.) to burn. Some cameras have a separate flash boards (such as NIKON 5700), prone to sealing off, should be carefully examined.

The solution: suspected of sealing off the back soldering again. Inspection and replacement of defective components.

9.

Fault phenomenon: one or a few key failures

Troubleshooting: damage, first with a multimeter to check keys requires key contacts and no leakage. Sometimes a key moisture leakage can lead to failure of a few buttons and even the entire camera. If the button is no problem, check the motherboard, cables, sockets, etc..

Solution: For wet or damaged keys can be used anhydrous alcohol scrub, and then dry with a hair dryer. The motherboard need to be carefully check to solve.

Maintenance Example: Konica Minolta Z3, three key failures, the use of extremely accurate. Open the machine keys are all good, then check the motherboard. 8 found that all the keys by an NEC single-chip management. Carefully check each pin of the MCU, and a few pins near the sewage sediment, and drying with anhydrous alcohol treatment, everything is normal.

10.

Fault phenomenon: does not recognize the card, or read and write errors

Failure to check: First, another card to try. Remove the card, usually the camera's card slot is broken. The CF card is more common generally barbarous plug lead.

The solution: replace the card slot. Generally have a variety of circuits and chip card slot below the replacement be sure to be very careful best professionals replacement.

11.

Fault phenomenon: LCD screen blank or show confusion, normal photo

Failure: LCD screen cable damage. Rotate the LCD machine common.

Solution: Replace the cable

Also seen some other fault:

A CANON A610, take pictures, can not playback after changing the motherboard. A CANON A-series cameras (the specific model forgot) and consumption greatly, a fully charged battery shooting more than a dozen of prompt power, battery and camera fever powerful. Normal after replacing the motherboard.

Maintenance Note: inside the camera is very precise, maintenance must be careful! To tear down the lens is best to find a clean place to avoid into the gray.

In addition there is a very important point: the camera's fault, cable accounted for a large part of. Damaged cable can not pick up enameled what cable must be replaced! If you pick up the magnet wire will damage up to a few months. Some place to repair digital cameras use the enameled wire to pick the damaged cable, fix the camera so can not make live. It must be noted.

System test design specification

Study of test specifications, test work to clear objectives and principles considering testing work to complete the project and its completion time; and intend to work procedures, staffing, technical support, and information collection and analysis, and other specifications. Although China has promulgated in 1995 GJB2547 outline of the equipment tested, outline from the demonstration, plan, implement, and verify a few stepped up testing of technical guidance and Nikon Coolpix P300 Battery Charger supervision, on promoting the application of test technology research and has a very big role. But the main reference to us military standard MIL-STD-2165 standard developed, lack of standards into concrete methods of design and technology. Designed for specific space system operability is not strong. Cause the above problems cannot be effectively resolved. To add a new test file, specification of aerospace product testing procedures, guarantee of test design and performance design of product function and the organic integration of guarantee system for test work has been carried out at all stages.

Test design workflow

We're working on test specifications to conduct research on the implementation of test design summary on the basis of the basic workflow, based on system design and development process, developing stages in the aerospace products development practices. As shown in Figure 1.

Stages of reasoning and programmes requiring testing requirements, test requirements and distribution. Within this period, the outline system design review and review of test; in systems development in the early stages, first to determine if the diagnostic program, develop and implement of testing and test for the inherent design of the design criteria. And then determine the FD (fault detection), FI (fault isolation) design strategies, design of related software and hardware, and then to analyze the design, Testability verification, product design and test analysis of iterative improvement method of test design to meet the requirements. Early in the assessment and review of test work. Development continued on the validation of test indicators, and to make recommendations.

Specification test provided for in item content and completion time, and other information that is reflected in work in process, guiding the aircraft system testing at all stages of work.

System test design method

Design and implementation of

Test design typically has two methods:

Product design while testing design

Completed parts or components directly by the designer test designs and assessment of work, finally by the device, system and system of graduated according to the test requirements for the evaluation and audit, to complete the system of test design. The advantage of this approach is due to designers familiar with the object being designed, repeated Panasonic DMW-BMB9E,DMC-FZ40/FZ45/FZ100,DMW-BMB9 Battery Charger less design, short design cycle, but designers of level design and testing technology of familiarity needs the very highest level, suitable for carrying out the tests are designed with a certain basis, and with a good test design environment units and departments.

Product design and test analysis of repeated iterations

Product designers after the design is complete, dedicated testing staff or independent bodies for test modeling, analysis, and assessment, testing of indicators of implementation of improvement and give comments, completed by repeatedly iterate the process improvement of product design and testing designs. The advantage of this approach is easy to implement, but the designer during the design and testing of staff requires repeated interaction, and longer design cycle.

At present, the lack of effective test of software for computer-aided design tools, design of product designers to test familiarity is not high. Therefore, using the second method of system test design is a more technical way possible.

Test design of the implementation process

Through product design and test analysis of repeated iterations of design for testability, Testability Analysis broken down into product design and synchronization, mutual interaction of two different kinds of work, reduces the testability design requirements for Testability design tools for designers and. General system design process based on performance indicators and design of programmes, preliminary and detailed design to hardware and software development and testing. As design features, test design also has a concurrent design process and system design, Figure 2 depicts a work system or a stand-alone test design process:

In parallel design, Testability Analysis and product design personnel in sync and in different stages of development to provide the corresponding testing proposals, ensure the smooth progress of the product design. Test design does not interfere with the original product design staff design processes and methods. Corresponds to a single machine, system, system level design, design for testability, Testability analysis results and based on the level of testing to JVC BN-VF823 Battery Charger the next level of design guide and audit, optimization testing resources, eliminating redundant testing, compatibility testing interface. Should as far as possible in the product design process using the same kind of Testability Analysis tool, so that at the next higher level of Testability model can be used by the next level of each unit test models directly generate, avoiding unnecessary modeling effort.

System test design specification

Study of test specifications, test work to clear objectives and principles considering testing work to complete the project and its completion time; and intend to work procedures, staffing, technical support, and information collection and analysis, and other specifications. Although China has promulgated in 1995 GJB2547 outline of the equipment tested, outline from the demonstration, plan, implement, and verify a few stepped up testing of technical guidance and Nikon Coolpix P300 Battery Charger supervision, on promoting the application of test technology research and has a very big role. But the main reference to us military standard MIL-STD-2165 standard developed, lack of standards into concrete methods of design and technology. Designed for specific space system operability is not strong. Cause the above problems cannot be effectively resolved. To add a new test file, specification of aerospace product testing procedures, guarantee of test design and performance design of product function and the organic integration of guarantee system for test work has been carried out at all stages.

Test design workflow

We're working on test specifications to conduct research on the implementation of test design summary on the basis of the basic workflow, based on system design and development process, developing stages in the aerospace products development practices. As shown in Figure 1.

Stages of reasoning and programmes requiring testing requirements, test requirements and distribution. Within this period, the outline system design review and review of test; in systems development in the early stages, first to determine if the diagnostic program, develop and implement of testing and test for the inherent design of the design criteria. And then determine the FD (fault detection), FI (fault isolation) design strategies, design of related software and hardware, and then to analyze the design, Testability verification, product design and test analysis of iterative improvement method of test design to meet the requirements. Early in the assessment and review of test work. Development continued on the validation of test indicators, and to make recommendations.

Specification test provided for in item content and completion time, and other information that is reflected in work in process, guiding the aircraft system testing at all stages of work.

System test design method

Design and implementation of

Test design typically has two methods:

Product design while testing design

Completed parts or components directly by the designer test designs and assessment of work, finally by the device, system and system of graduated according to the test requirements for the evaluation and audit, to complete the system of test design. The advantage of this approach is due to designers familiar with the object being designed, repeated Panasonic DMW-BMB9E,DMC-FZ40/FZ45/FZ100,DMW-BMB9 Battery Charger less design, short design cycle, but designers of level design and testing technology of familiarity needs the very highest level, suitable for carrying out the tests are designed with a certain basis, and with a good test design environment units and departments.

Product design and test analysis of repeated iterations

Product designers after the design is complete, dedicated testing staff or independent bodies for test modeling, analysis, and assessment, testing of indicators of implementation of improvement and give comments, completed by repeatedly iterate the process improvement of product design and testing designs. The advantage of this approach is easy to implement, but the designer during the design and testing of staff requires repeated interaction, and longer design cycle.

At present, the lack of effective test of software for computer-aided design tools, design of product designers to test familiarity is not high. Therefore, using the second method of system test design is a more technical way possible.

Test design of the implementation process

Through product design and test analysis of repeated iterations of design for testability, Testability Analysis broken down into product design and synchronization, mutual interaction of two different kinds of work, reduces the testability design requirements for Testability design tools for designers and. General system design process based on performance indicators and design of programmes, preliminary and detailed design to hardware and software development and testing. As design features, test design also has a concurrent design process and system design, Figure 2 depicts a work system or a stand-alone test design process:

In parallel design, Testability Analysis and product design personnel in sync and in different stages of development to provide the corresponding testing proposals, ensure the smooth progress of the product design. Test design does not interfere with the original product design staff design processes and methods. Corresponds to a single machine, system, system level design, design for testability, Testability analysis results and based on the level of testing to JVC BN-VF823 Battery Charger the next level of design guide and audit, optimization testing resources, eliminating redundant testing, compatibility testing interface. Should as far as possible in the product design process using the same kind of Testability Analysis tool, so that at the next higher level of Testability model can be used by the next level of each unit test models directly generate, avoiding unnecessary modeling effort.

Vsr based rectifier tube for maximum pressure drop ≤ 0.7V, inductance of winding maximum resistance voltage drop VL ≤ 0.1V, other Nikon D50 Battery Charger lines maximum voltage drop Vr ≤ 0.1V, original side MOFET and line voltage drop Vsw ≤ 0.3V, transformer efficiency ¦ç ≥ 98%. Other parameters are:

Vs: transformers under voltage

Vp: transformer original side voltage

Input voltage: Vin=390~400V

Output current: Io=1A

Output voltage range: Vo=50~70V

Output power: Pomax=70W

Maximum duty cycle: Dmax=0.45

Switching frequency: f=80kHz
Current density of the wire: J=4A/mm2

Core magnetic flux density variation: d B=0.2T

(1) calculate turn ratio

(2) calculate the total apparent power

(3) calculate the area core Windows product

Kw: transformers window coefficient, coefficient of window rough take first 0.4, Deputy of the Central Plains this design side windings are made of copper; Kf for two-transistor forward converter circuit can consist of the following formulas to calculate:

(4) in selecting magnetic cores

According to the Ap search core manual, determine the core structure for EE42/21/15, magnetic core materials for Siemens N67 materials, effective cross section: Ae=234mm2, window area: AW=250mm2,AexAW=5.85cm2>Ap.

(5) the original edge is computed, the Deputy winding turns

Original side switching valve for MTP4N80, rated current of 4 a, pressure resistance the 800V. D1~D4 4 output rectifier diode fast recovery diode DSEI1206A only, 2 parallel use only as a continued flow diode. DSEI1206A reverse soft recovery characteristics of output spike voltage decrease, a reverse recovery current translation to the original side is also small, original MOS2FET opening losses reduced. 65V output voltage, output current 1A, the transformer temperature rise is less than 30 degrees centigrade, efficiency is 93%.

Test results

PDP power supply design completed need for high and low temperature impact testing, EMC testing, load characteristics, Panasonic Lumix DMC-FX33 Battery Charger  power factor, the full load power factor test for >98%, following various other tests.

Basic performance indicators

PDP power supply basic performance indicators table as shown in table 1.

Environment test

A. low temperature test:-5 ° c, power can start working, test load regulation, rate of voltage, voltage accuracy, output over-current protection, output over-voltage protection point, set the precision, items such as peak to peak noise.

B. high temperature: 50 ° c, power can start working, test load regulation, rate of voltage, voltage accuracy, output over-current protection, output over-voltage protection point, set the precision, items such as peak to peak noise.

EMC testing

A. Voltage dips, drops and short-term changes in voltage test simulation of three-phase ACSOURCE power grid, Voltage dips, drops and short-term changes in voltage power supply when it works.

B. grid special waveform test:

1) simulation of three-phase ACSOURCR harmonic input, prototype works;

2) single phase ACSOURCR analog power spikes, Burr type, prototype works; when the peak voltage 400V, shutdown protection.

C.-noise immunity test

Power input port in coupling of common-mode noise voltage of 3kV, prototype work.

D. meet JVC AA-VF8 Battery Charger ANSIIEEEC62.41-1991, B3 level, mixed 1.2/50 eight-twentieths µ µ s and s-wave, 6kV/3kA.

Component temperature rise test

Loaded with all components under temperature below 40 degrees centigrade.

PDP plasma display screen is appeared on the international new products in recent years, its design is more complex, requires an output number, small size, wide voltage adjustment range, high voltage, low ripple, low noise, low EMI, switch machines have a strict time limit. PDP power supply have already been successfully applied in the design of a well-known brand on a 42-inch plasma display, after two years of thousands of plasma display panel using the validate, repair rate is less than 0.05%, prove the reliability of its design is very high.

One of the technical requirements of this series belongs to the technical requirements of energy-saving. As a follow-up to the implementation of the People's Republic of China Energy Conservation Act, save energy, protect the environment, reduce energy loss of AC power system trap run. Energy-saving, guide enterprises to energy-saving technological progress, special development of this specification.

The technical requirements under AC electric trap production and use in developing the system.

This technology trap requirements apply AC power systems, their performance meets the requirements of GB/T7330-1998 the AC power system trap.

The technologies required by China's energy-saving products certification Management Committee (CCEC) proposed and JVC BN-VG121 Battery Charger centralized.

Trap AC power systems technical requirements of energy-saving products certification

1. scope

Provides this technology trap evaluating values of energy conservation for AC power system, test methods and test rules.

Requests for 35kV and above all this technology trap voltage AC power system. Hereinafter referred to as trap.

Application of energy-saving products is mass production of conventional products.

Technical requirements do not apply to this special design single small batches of trap and trap of DC transmission system.

2. reference standard

The following standards include provisions, quoted by the technical requirements and technical requirements of this provision. The technical requirements for publication, version shown are valid. All standards will be revised, the technical requirements of the parties should explore the possibilities of using the following criteria to the current version.

GB/T7330-1998 AC power system trap

3. definitions

This specification adopts the following definition. Other relevant parts of the term, see GB/T 7330-1998.

3.1 power loss power-frequency loss

When the rated continuous current flow through the trap, the power loss of the trap.

3.2 trap energy-saving evaluation of value of the evaluating values of energy conservation for line traps

Evaluation of trap levels of energy-saving value of high-frequency loss, this loss of value when the value is converted to 75 ° c.

4. product classification

4.1 trap according to their main winding rated inductance can be divided into:

0.2mH?0.3mH?0.5mH?1.0mH?2.0mH

4.2 trap according to the rated continuous current is divided into:

200A?400A?630A?800A?1000A?1250A?1600A?2000A?2500A?3150A?4000A

4.3 trap according to the rated short time current is divided into:

5kA?10kA?16kA?20kA?25kA?31.5kA?40kA?50kA?63kA?80kA

4.4 above three parameters for each combination of a size variety of the trap.

5. technical requirements

5.1 wave trap coil DC resistance

Submitted by a certificate issued by the inspection bodies of type test report shows values differ by not more than ± 2%.

5.2 trap evaluating values of energy conservation

Specifications of trap frequency loss shall not exceed the requirements of table 1 value.

5.3 quality factor

Trap the quality factor should satisfy the requirements of 6.1.2 the terms GB/T 7330-1998.

5.4 blocking impedance/blocking resistance

Information should be published with the application side or by a qualified inspection bodies of type test reports issued by the same.

Weight 5.5 Visual inspection and measurement

Structure and applications of the products described in the published information and providing information to the certification body. Height and diameter dimensions of process deviation of ± 1%, weight of process deviation of ± 5%.

6. test method

6.1 General requirements

In accordance with the requirements of the GB/T7330-1998 chapter in the 18th.

6.2 block impedance/blocking resistance

In accordance with the requirements of article 19.7 GB/T7330-1998.

6.3 wave trap coil Panasonic Lumix DMC-ZS7 Battery Charger DC resistance

Stable room temperature ? measurement of DC resistance of trap, trap and record temperatures. Measurement of DC resistance at the temperature according to the following conversion to 75 ° c

T+75

T+?O

R75= RO

Type: RO-temperature of ? is measured resistance (?);

R75-conversion to 75 ° c resistance (?);

T-countdown of the temperature coefficient of the wire, aluminum wire 225, copper for 235, Al-mg-SI alloy wires for 278.

6.4-frequency loss

Power loss measurement using wattmeter method, the power factor wattmeter shall not exceed 0.2. Static test articles on Interior over 3 hours, in the rated continuous current power loss measurement, and according to the following conversion to 75 degrees centigrade:

P75=I2• R• K+(PC-I2• R)/K

Where: k = (T+75)/(T+ ?)

Type: I-rated continuous current (a);

T – room temperature (?)

R-trap in room temperature ? DC resistance (?);

PC-trap in the room temperature ? frequency loss measurement (w).

When power loss and energy saving on the value of the relative deviations within ± 2%, that is,

≤-2% ((P75-P review)/P comment) when ≤ +2%, to improve the stability and reproducibility of measurement should be under the rated continuous current stability after the power loss measurement of temperature rise, and commuted to 75 degrees centigrade.

6.5 the quality factor

Admittance measurement trap under the bridges in frequency is 100kHz equivalent of equivalent resistance and reactance x r, measuring loop as small as possible, to exclude the remaining effects of impedance. Quality factor according to the following calculation:

Q =X/R

7. sampling, inspection and decision rules

7.1 sample

7.1.1 China Center for energy conservation product certification for people in the business end of the production line, finished product warehouse or sample in the market.

7.1.2 randomly selected each specification 3 samples.

7.2 test

Inspection procedure: the field on each of the specifications of 3 DC resistance test samples, meet the requirements of section 5.1, and then randomly selected from a sample, sent to the inspection bodies under the 5th chapter of  JVC BN-VG107U Battery Charger the pilot project. If measured have a DC resistance of the sample site does not meet the requirements of section 5.1, then determine if the product does not meet the requirements of energy-saving evaluation of value.

7.3 determination rule

If the inspection bodies meet all requirements for the 5th chapter of the inspection items, energy-saving product certification testing will determine if the product has passed. Otherwise, do not pass.

8. Managed elements and materials

Should contain information such as product specifications, subcontractors.

8.1 aluminum wire;

8.2 end;

8.3 insulation;

8.4 insulation pads;

Insulated spacers between layers of 8.5;

8.6 encapsulated composite insulating materials (enclosed).

After the products have been certified, included in the managed parts and materials are subject to change, applications must be reported to CECP, CECP related projects GB/T7330-1998 and according to the technical requirements of this standard passed the inspection and after approved by the CECP, before it can be changed.

9. product description

Applicant in the application for energy conservation product certification for information that should be provided according to the following descriptions:

9.1 wire specifications;

9.2 outer diameter and inner diameter size;

9.3 highly;

9.4-side arm;

Weight 9.5;

9.6 main line number of layers;

9.7 number of insulation;

9.8 the outer insulation pads;

9.9 nameplate;

9.1 a ruler mark color photos.