The Clever Apprentice

Wow, can you feel the heat? It’s getting hot out here in my neck of the woods. We’re just beginning to put splitters away and break out the tillers.

So, I was browsing around looking for things that would help me through this season and found some great resources to share with you now.

Rototillers

There are a ton of rototiller choices out there. Learn how to find and buy the right rototiller for you. It really depends on a lot of things. Search for the right tiller in a store, then compare online. You can get some of the best deals I found out there on a rototiller from the Rototiller Store. I can’t believe how easy the tiller store website is to use. View the site in a new window - just right click on the link and click ‘new window’. They make it easy to find the deal that’s right for you because you can review a ton of tillers and their prices within a few mouse clicks.

Energizing

Ok - this doesn’t look like it belongs, does it? Well, I found this awesome chance for diversifying my income and having the energy to work hard in the garden with my rototiller. Do you like to try things before you buy? I do too. I can’t believe how good and energized I felt after drinking this. Do you need to stay up all night? This stuff will do it to you. Boost of energy all night! This is the healthiest energy drink I know about. What do you think? You need to go pounce on this efusjon opportunity right now. Don’t wait another second - join the ‘a’ team today. They are successful. I need you to do this - for you and for me. It’s completely worth it and by jumping in early, you have a good chance at doing well. Try it today! Sign up!

Splitter Maintenance

You haven’t put away that wood splitter yet?!? No problem. Sheds help protect your wood or log splitter during storage. Keep the splitter sparkly. Browse through the site linked above for more information on log splitters. You can find almost any and all types of wood splitters on the market and their prices and info on this website. Don’t forget about the site when you go for your next splitter.

Alright! Hope this assisted you.

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.

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. Swith 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. Swith mode power transformer is a little bit difficult to rewind because of the small size and low price.

Jestine Yong is a electronic repairer and a writer. For more information about electronic repair please visit his website at
http://www.noahtec.com/electronic-repair-articles.htm

Laptop batteries come in all shapes and sizes also differ in their chemical composition. The chemistry of a battery refers to the chemical make-up of the cells inside the outer casing. The most common chemistries used in laptop batteries are:

NiCad (Nickel Cadmium) This is the oldest technology and is the least commonly used nowadays. NiCad batteries are prone to the “Memory effect” and are heavier than the newer technologies. NiCad is not environmentally friendly chemistry as it contains heavy metals, which cannot be disposed of in landfill sites. Most manufacturers have stopped producing batteries of this type chemistry. As an end user it will be increasingly difficult to source these batteries. The best alternative is external battery packs.

NiMH (Nickel Metal Hydride) these batteries are less likely to be prone to the memory effect and have a much better power to weight ratio than NiCad. This is a commonly used chemistry. These batteries are also being phased out by most manufacturers. However, many have lithium-ion versions that are compatible. Always consult the manufacturer or a reputable laptop battery supplier.

Li-Ion (Lithium Ion) - This is becoming the dominant technology due to its excellent power to weight ratio. Such considerations are becoming more important as mobile devices become smaller and lighter and battery weight becomes significant. Another plus point for Li-Ion is that it doesn’t suffer the memory effect at all. These batteries do have a tendency to lose charge quickly towards the end of their effective life span. If this starts
to happen the battery must be replaced.

These three technologies are quite different in the way they charge and therefore should not be substituted unless the device has been designed to take different chemistries. The owner’s manual will describe which batteries are suitable.

Mansi aggarwal writes about Lithium Ion laptop batteries

Where do you find that perfect cell phone that you can afford? Finding any phone can be a challenge, especially if, like me, you need it at a reasonable price. It may seem like a nextel phone is one of those things you can just find anywhere, but believe me, that is not necessarily the case when it comes to finding one at a good price. I have found, though, that there are three places you should look before you make that final purchase. For that perfect and affordable nextel phone, check online, in a department store, and in the kiosk stores.

The first place to look for nextel phone would be on the internet. Many department stores and retailers have websites that offer nextel phones for sale. These sites often have special online only deals that can assist you in finding the price you are looking for. Be sure to go to a search engine and seek out nextel phones as well. There are sometimes retailers that only exist on the Internet that will have better prices on phones than even mainstream retailers might.

The second place to look for a nextel phone at a good price would be at a department store, physically. Often times at stores, there are discount or clearance deals, including nextel phones, which may offer even better prices than you found online. The other advantage to a store’s physical location is that you will be able to pick up, try out, and feel the nextel phone to know if you like the way the phone works or feels in your hand. Either way, a department store location or retailer is a stop you really should make in your search for a nextel phone at a good price.

The third place to scope out for a nextel phone is one that may not be for everyone. Some people are uncomfortable with kiosks in the mall, but they can be fantastic for getting a good price on a phone that you want. You have to keep an eye out and find a piece that is in good condition and of a good brand, but you would be surprised what you will see at a good kiosk even if it is not manufacturer specific. A similar place to look that is not quite second hand is an overstock store. Many stores now take cell phones from larger retailers that have been overstocked. They get a discounted price and pass that along to you. You may find a great nextel phone at an overstock store that is what you want only at half the price.

Finding a perfect nextel phone at just the right price can be a difficult proposition. You don’t want to buy just any brand to save a buck, but you also aren’t made of money. Take the time to search all three of these places to find the what you need. Check the internet first, the department store, then either a kiosk or overstock store to see if you can catch a deal at just the right moment. Take your time, do your research and you will be surprised at how great a deal you just might find on the nextel phone you want.

If you would like to find more of my personal articles on cell phones please check out my technology website!