Testing a Transformer - How To Accurately Test A Transformer

There is two types of transformers in the market- linear transformer and switch mode power transformer. The transformers design is different. Sometimes it is just referred as ac transformer. Linear transformer mostly used in radio, project kits, VCD and etc while switch mode transformer can be found in Monitor, Tv, Fax and so on.

A transformer consists of two or more coils wound on the same core. For power transformers, the core material is usually iron. For a radio-frequency transformer, the core material is usually ferrite or air. The basic property of a transformer is to change AC voltage. A transformer cannot change direct current voltage. A step down transformer has a lower AC output voltage at its secondary winding than the AC input voltage to its primary winding. Conversely, a step up transformer has a higher secondary than primary voltage. The transformer laminations or coating of shellac, enamel or varnish is to insulate adjacent turns from shorts between winding. I will not go too details about how transformer work and transformer calculation as you can read more details from most electrical and electronic transformers books.

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How to test transformers: Transformer failures are relatively rare in most electronic equipment, compared with other components. If too much current goes through a coil or winding, the winding heats up and can either open up completely, or the insulation between turns of wire can break down, causing the coil to be partly or completely shorted.

Just like a coil, you can check continuity of any primary or secondary transformer winding. The actual value of DC resistance you read is rather meaningless, but at least you will know whether a winding is open. Checking linear transformer is quite straight forward. Apply the ac voltage to the primary winding and expect output voltage at the secondary side. No or low output voltage means the transformer winding has open or shorted winding. Look for any evidence of overheating, such as darkened or blackened areas or a burnt smell.

About how to test a power transformer-it is a little bit complicated. You cannot apply ac voltage to the equipment and expect the desire output at the secondary side without connect to load otherwise over voltage will happen (because you have removed all the secondary load) and will blow the power section which consist of power fet, pwm ic and etc. Switch mode power supply are designed to run with load while linear transformer can be test without load.

The best way to test a switch mode power transformer is first remove it from the board. Check only the primary winding as secondary winding failures are exceedingly rare. How do we know which one is the primary winding? Trace from the big filter cap the positive pin to see where the circuit goes. It will go to one of the pin of the transformer. Then look for the power fet middle pin which is the Drain and it will lead to another pin of the transformer. This two pins is the primary winding of the transformer. Checking the resistance of the primary winding only can reveal whether it is open but it cannot check if it has developed a shorted winding. Only by using a ringer test you will know if it shorted or not. A shorted turn in the primary winding can cause the power section to blow.

The cheapest ringer tester that i came across is Dick Smith LOPT METER or flyback tester. Just connect the probes to the primary winding and the result are instantly seen from the Led bar graph. 4-8 bar represent a good winding, 1-2 bar represent partial short and if the led goes off means there is a heavy short in the winding. Besides checking the transformer it can be use to check B+ COIL, horizontal yoke coil and flyback primary winding and ballast (choke).

The expensive ringer tester is from sencore equipment. Sencore LC102 and LC103C besides checking capacitor it also have the capability to check all kind of winding. Whether it is a low voltage transformer, high voltage transformer, current transformer, pulse transformer, electric transformer, custom transformer this equipment will be able to check and test it.

If you do not wish to invest on this tester you may use a light bulb to check it. Remove one of the primary winding pin and connect a 60 watt light bulb. One end to the circuit while the other to the transformer pin. If the bulb light and didn't goes off suspect a shorted winding and if the light goes off, the winding is ok.

Transformer repair is not easy and it require a good skill to do it. Most of the transformer repairer preferred to rewind bigger winding such as fan, car alternator and starter. Switch mode power transformer is a little bit difficult to rewind because of the small size and low price.

Testing a Transformer - How To Accurately Test A Transformer

How Do I Get Rid of Mice in Our RV?

I am by no means an expert on pest and rodent control, but after
researching the subject I can offer a few ideas that seem to
work for other RVers.......

The first and most important step is to try and prevent mice
from being able to access you RV. This can be difficult because
they can enter the RV through some very small areas. Start by
inspecting the underside of your RV for any gaps or holes. Fill
these gaps using silicone or expanding foam. A word of caution,
if you never used expanding foam before you should experiment
with it on something other than your RV first. When it dries it
can expand a great deal more than you expect.

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Next, open drawers and cabinet doors inside your RV. Look in all
of the corners and crevices, especially where plumbing and
wiring enter the RV. If you can see any daylight mice can get
in. Again, fill these areas with silicone or foam.

Mice also enter through vents like the furnace. You can purchase
wire mesh type covers from your RV dealer that can be installed
over these vents. Many RVers suggest you spray some type of
insect spray (that contains mint oils) around the tires to
discourage mice. The only problem with this is you would need to
do it every couple days. I don't recommend any type of poison.
It can take several days for the poison to work and the mice
will usually die somewhere that you can't find them. If this
happens you may never get rid of the smell.

Other RVers recommend using mothballs throughout the RV and in
storage compartments, if you don't mind the smell of mothballs.
The alternative to mothballs is dryer sheets, like Bounce.
People swear they work and the smell is much more pleasant. If
you are close to where your RV is being stored you may want to
use conventional mouse traps and check for mice every few days.
The only problem with traps is the bait can actually attract
mice. Of course you will want to remove any food from the RV
that can also attract mice.

Happy Camping,

Mark

Copyright 2006 by Mark J. Polk owner of RV Education 101

How Do I Get Rid of Mice in Our RV?

CD/DVD Duplicators and Their Importance

The evolution of the CD/DVD duplicator has been a blessing for businesses of all types, helping them deal with data storage and dissemination. From publishing annual reports for investors and shareholders, to availing training material for staff and personnel, it is all made possible through the production of large quantities of discs copied with CD/DVD duplicators.

Running a business is getting tougher these days, being continually subjected to all forms of competition and challenges on its road to success. One such challenge is the efficient management of data. Correct information or data management is the lifeline of every business, and the loss of key information is sure to create chaos. Thankfully, technology has provided a reliable solution to problem.

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The CD/DVD duplicator, although it has been around for a while in the IT sector, plays a major role in providing a fast, easy and significant storage solution. This piece of sophisticated equipment has evolved into a potent weapon behind the success of any business. All size of business has found it more than useful in creating and duplicating all forms of content on all types of optical media, from CD, up to DVD R (both single-layer and double-layer), and more recently Blu-ray media. So let's take a look at some of the features of a duplicator.

Generally, they don't need a computer to operate (i.e. they can function stand-alone). Some though, do have a USB port to connect to a hard disc or PC as per requirements.
They have a built-in high storage hard disk for storing optical disc images.
They can burn at speeds of 48x for CD and 24x for DVD.
Some duplicators have the capacity to burn 1000 discs.
Support any format of recordable media like CD-R, CD-R(W), BD-R, BD-RE, BD-R DL, BD-RE DL, DVD+/-R, DVD+/-R(W) and DVD+/-R Dual Layer.
They come in varying configurations, starting at 1 drive and going up to 15 or more drives for faster duplication of larger jobs.
User friendly control panel.
Auto recognition of master and blank discs for recording.
Password protected.
Automatic verification of data after recording.

These key features of a CD/DVD duplicator should be enough to convince any business of the benefits of this extraordinary piece of equipment. To start with, it greatly simplifies and automates the creation of backup copies of important material and key information, vital to the survival of any business.

Businesses can also provide management, investors, shareholders and other interested parties, with company reports and related information by producing large runs of copies, easily and quickly. The same process can also be used to provide training material for new employees and staff. Businesses can also create large quantities of marketing material for potential clients and customers, helping develop brand awareness. Finally, the gradual reduction in the price of recordable media over the years, is an additional boon to the businesses making this a cost effective means of information storage.

Presently, there are several manufactures producing different categories of cd dvd duplicators which are not only reliable, fast and of superior quality, but also affordable and easy to use. Among the best and most trusted brands on the market is that of Microboards.

CD/DVD Duplicators and Their Importance

Dual Screen Portable DVD Players

The portable DVD players are a scaled down version of the ones that we use at home - they are perfect for using in the car or if they are battery powered, could keep your kids entertained even if you go on a picnic or camping. In the past, they suffered from a number of drawbacks such as poor audio quality, support for limited file formats, and used to be quite expensive as well. However, the advancements in the electronics industry have brought the prices down, the picture quality is often outstanding, and the sound quality if not perfect, is at least adequate.

Since more often than not, they are used as in-car DVD players, the dual-screen models are perfect. They are mounted on the front seats' headrests, and they allow at least two backseat passengers to enjoy the movies, which is especially useful if you do not want your kids bickering while on the road. In most cases, the dual-screen DVD players have only one play unit, which means that the same movie is shown on both screens. Depending on the make and the model, various power options are available, but if you intend to use the player outside the home or vehicle, then a battery-powered one is a must.

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The twin-screen portable players are more expensive than the single screen ones, but they could be seen by larger audience, and their advantages far outweigh the price difference. They are also manufactured and sold by some of the top companies in the World and are often very well built, sturdy, and come with amazing number of different functions. Almost all of them make use of a skip protection, which ensures better viewing experience, and some of the top models have power resume feature as well. The players, which have been built in the past few years, also support a dozen of the most widely used audio and video file formats and play not only DVD and audio CDs, but could also display JPG images. Despite the fact that they have been created for entertainment, they could be easily used by agents and sales representatives for presentations as well. The portable DVD players are very easy to set up, have good picture quality, and some of them support widescreen formats as well. Before deciding on which brand and model to buy, you should also find out what kind of accessories the player comes with. AV and mains cables would allow you to use the unit at home, and watch the movies on your large TV screen if you choose to, and the availability of a remote control would let you operate the player from the front seat of the car.

Dual Screen Portable DVD Players

How to Backup Pictures to DVD

In this tutorial I'll be teaching you how to backup (some of) your pictures to DVD using the built-in DVD burning software in Windows Vista. The only thing you'll need for this tutorial is a blank DVD. A blank DVD can hold about 4,500 Megabytes of data. Each of your pictures is probably about 1.6 megabytes. Based on those two sizes you should be able to backup about 2,812 pictures per DVD. Ok, lets get started.

1. Put a blank DVD into your DVD Burner and close the drive.

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2. Right click a folder containing some pictures and then click "send to" the select "DVD RW Drive".

3. A Window will appear asking you to give the disc a name. Enter whatever name you'd like.

4. Windows Vista will begin formating the DVD. After the format is completed Windows will then start to burn your pictures to the disc. This process can take approx. 1 to 30 minutes.

5. After the disc has completed the burning process a window will pop open showing you the contents of the burned disc.

6. Click the eject button. The disc will not eject right away because windows needs to finalize the disc. This process can take about 5 minutes. When that's completed the disc will pop out.

At this point the those pictures have been backed up DVD. They are still on your computer and you should leave them there because it's always good to have your data in two places.

How to Backup Pictures to DVD

Types of HD DVD Software

HD DVD or High Definition Digital Video Disc is a type of disc format manufactured by Toshiba. It provides a high definition video for great video quality and it is specially designed to store up to 60GB of data depending on the layer and its physical size. However, it is no longer produced due to the existence of Blu-ray discs. However, there are still a lot of people who are still using this type of this and to read the format of the disc it requires the HD DVD software. Here, I would like to explain to you on several software available that are designed to cater for various purposes.

The first type of software that helps to read the HD DVD is the DVD burning software. Just like other burning software, it transfers the data from your computer and places them into the disc. You can burn those discs in two ways. One is to burn files and documents where you can just drag or load the files into the software and start burning your disc. As for burning movies or other videos, it requires some strict procedure in order to burn them correctly. Look at the help section for the proper method.

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Second HD DVD software that caters this format is DVD conversion software. You should know that there are a lot of formats available in storing data. Not every player can play HD DVD and this software plays a very important role to enable the disc to read at other players. For instance, we can change the '.avi' format into '.mkv' for better video quality and compatibility.

Lastly, there is the DVD copying software that offers you to make a copy of the disc content into your computer or we call it to write the files into the computer. By doing so, you can burn the content of the earlier disc into another disc.

Types of HD DVD Software

How to Clean a DVD Player Laser in 8 Steps

Whether your DVD player is malfunctioning or you get a no-disk error you may need to clean out the player. Inside your player is a laser pickup which reads your DVDs and allows you to access or view the content. To make your DVD player functioning again you simply need to properly wipe the laser pickup clean following these simple steps.

Before following these steps let us just look at what we are basically need to do. We need to basically remove the DVD head and electronics out of the player case to have easy access to the actual laser pickup enabling us to clean it properly. Once cleaned it is just a matter of putting everything together again.

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Before following the steps, make sure the laser pickup lens is the actual problem. Inserts a few DVD is into the DVD player to confirm the problem is actually the lens. If some DVDs work and others do not, the problem is clearly not the player. If none work, there can be a wide variety of reasons why a DVD player is not functioning properly anymore. But, it is highly likely that the laser pickup lens has simply become dirty.

What You Need to Clean the DVD Player

lens cleaner disc screwdriver cotton swab isopropyl alcohol flashlight (optional)
How to Clean DVD Player Laser

Step #1 - Lens Cleaner Disc - The first thing you need to do is to get or borrow a lens cleaner disc to try and clean the laser pickup. These lens cleaner discs usually do a terrific job cleaning the laser pickup. Next, try out a few more DVDs to see if the problem is resolved or not and if you have to take further steps to clean out to the pickup up manually or not. If the player still does not work follow step 2.

Step #2 - Removing the Outer Casting - Unplug the player from the power supply and remove the screws of the outer casting. You will now see the plastic head of the DVD player which can be actual electronics attached to it.

Step #3 - Opening the DVD - The next thing we need to do is get the plastic head with electronics out of the DVD player case. In some cases the tray of a plastic head has a tiny other casting attached to it. To remove it, simply plug in the power supply, power on the DVD player, open up the player, power off the DVD player and unplug the power supply. Now, simply detach the tiny outer casting from the tray.

Step #4 - Detaching the DVD Head - Next, we are going to unscrew the DVD head with electronics from the main board. Thanks to step 3 we can easily remove the head by unscrewing it from the main board and unplugging any and all cables going from the head to the main board.

Step #5 - Detaching Electronics from Head - Now you will have the DVD head in your hands, being the plastic mechanism, a clamp and the actual electronics. Remove the clamp. Look for the actual laser pickup which has a blue tint to it. If you have trouble finding the laser pickup, you go to shine a light to detect any reflections. If you can now see and easily access the actual laser pickup for cleaning already, there is no need to detach the electronics from the head. If not, you need to first simply detach the electronics from the head and then follow step 6 on how to properly clean the laser pickup.

Step #6 - Cleaning the Laser Pickup - Now that you have easy access to the laser pickup, use a cotton swab and some isopropyl alcohol and gently wipe the lens. Use the other end of the cotton swab to dry it. Now wait a few minutes and let it dry.

Step #7 - Putting Everything Together Again - Now that the laser pickup lens is clean again we can partially put everything together again and test the efficiency of the lens. Attached the electronics to the head again, attached the clamp, attached the head to the board again, attach all the previously detached cables onto the main board again, and plug in the power supply to test a few DVDs. Power on the DVD player, insert a DVD and test the disc reader's efficiency. If the DVD works you have effectively cleaned your DVD player. If not, follow the steps again and try to clean the laser pickup a bit more thoroughly.

Step #8 - Attach the Outer Casting - Put the power off again, unplug the power supply in screw all the outer casting parts back onto the DVD player.

You DVD player is now cleaned and ready to be used again!

How to Clean a DVD Player Laser in 8 Steps