| The transformer is an electrical device, | | | | a printer or a VCR, you will need a |
| which transforms voltage through magnetic | | | | transformer. Both of these category of |
| coupling with no moving parts. It consists of | | | | appliances and devices can be run by a |
| a magnetic core, with two or more coupled | | | | transformer, but only the electric appliance |
| windings, which either steps up or steps down | | | | can be run with a converter. A word of |
| the incoming voltage. This is done by the | | | | caution in here is that, while transformers |
| transfer of energy from one circuit to the | | | | are designed for long term continuous |
| other, through the magnetic core. These | | | | operation, converters on the other hand can |
| windings are generally termed as Primary and | | | | operate for an hour or two at a time.In order |
| Secondary windings. The electromagnetic field | | | | to understand this better, we must understand |
| thus created under goes a process of | | | | the formation of a AC voltage. The |
| expanding and collapsing around the conductor | | | | alternating current voltage appears as a |
| and this changes the induced current, with | | | | sine-wave, and depending upon the country you |
| the formation of an out put from the | | | | are in, the frequency of this sine-wave is |
| secondary coil, either stepping up or | | | | either 50Hz or 60Hz. Now, if you look at a |
| stepping down the input voltage.In order to | | | | converter output, you would see that the |
| understand the function of a transformer, | | | | upper half of the sine-wave has been chopped |
| only two sets of windings are considered. | | | | off, where-as, in a transformer the sine-wave |
| When the main AC voltage is applied to the | | | | remains in-tact. The electrical devices, |
| input of such an electrical device, the | | | | like, iron, heater, a hair dryer, etc, would |
| alternating current in the Primary winding | | | | run with such a converter, but a computer, a |
| creates a time varying magnetic flux in the | | | | printer or a VCR can be damaged if you |
| core. This induces an AC voltage in the | | | | attempt to operate those with a converter.The |
| secondary coil, which is either the step up | | | | frequency is the number of times the |
| or step down voltage of the device. The | | | | alternating voltage alternates each second. |
| terms, step up and step down are used with | | | | One such alternating cycle is termed as |
| respect to the input voltage of the device. | | | | Hertz, having Hz as the short form. This |
| Therefore, if your equipment has been | | | | cycling wave is termed as a Sinusoidal Wave. |
| specified as input voltage 110 Volts AC, and | | | | In the U.S. and the rest of North and Central |
| if you are in one of those countries where | | | | America, with some parts of South America, |
| the mains power supply is 220 Volts AC, you | | | | the alternating current suppy is 60Hz. In |
| will need a step down transformer to run your | | | | Europe and rest of the world it is 50Hz.There |
| equipment.In high tension power transmission, | | | | is a similar electrical device called |
| where huge towers carry the cables which | | | | Inverter. The purpose of this equipment is to |
| brings the power to cities, towns and | | | | convert Direct Current (DC) voltage to |
| villages, step up transformers are used as | | | | Alternating Current voltage. This device has |
| the power leaves the power stations and as | | | | many applications, for example, to provide |
| they approach the destinations, the voltage | | | | appropriate limited AC power supply to |
| is stepped down to the required mains supply, | | | | devices like, electric fans, lights, etc. |
| before it is distributed amongst the | | | | This inverter takes the DC voltage from a |
| consumers. The reason for stepping up the | | | | battery, like a heavy duty car battery and |
| power as they leave the power station is for | | | | converts that into an appropriate AC voltage. |
| the fact that,as it travels down the long | | | | Such supplies are limited because of the |
| power cables, there are power losses in the | | | | capacity of the battery capability and |
| way, and the supply can reach the | | | | depending upon the battery the ampere-hour of |
| destinations in a proper specified power | | | | the output can be increased, resulting in |
| level to be stepped down as required by the | | | | longer period of operation. The battery will |
| consumers. In this application there are good | | | | need charging once it discharges.There are |
| many use of transformers are made.The | | | | variable transformers, which are known as |
| transformer is the most simplest of all | | | | Variacs. The principle is that the output |
| electrical devices and its basic principle | | | | voltage of this transformer can be manually |
| has not changed over the last 100 years, | | | | varied with a fixed voltage as its input. For |
| though the material used in such transformers | | | | example, with a 110 Volt AC supply at the |
| and its design continue to improve. It has a | | | | input, you can vary the output voltage from 0 |
| very important application in transforming | | | | to 110 Volts AC. The typical applications of |
| electrical energy, both for consumer use and | | | | these transformers are in testing devices for |
| power transmission. In a similar way, audio | | | | its lower and higher input voltage operation |
| frequency transformers have been used in | | | | levels, quality control in testing equipment |
| earlier experiments in development of | | | | in burn-in condition, temperature and |
| telephones. These are still found in many | | | | lighting control, etc.Transformers are |
| electronic devices. The transformers come in | | | | essential devices to operate any electrical |
| various sizes, depending upon the application | | | | or electronic equipment. As far as main |
| it is required for. It comes in the size of a | | | | supply voltage is concerned, if you are |
| thumb nail to huge units for the power | | | | visiting Europe or any other country in Asia, |
| transmission applications of national power | | | | the devices that you are taking with you will |
| grids. They all operate with the same basic | | | | not operate in the mains supply voltage |
| principles.The core of the transformer, as we | | | | available in those countries. It is therefore |
| have seen above, may be made with various | | | | necessary that you take with you the right |
| materials. These include:Air - This is ideal | | | | device which can provide you with the right |
| for high frequency transformer, with | | | | operating voltage for your equipment.110-220 |
| application in Radio Frequencies and provides | | | | Volt Electronics - A multisystem TV is a TV |
| least coupling.Iron - All so called iron core | | | | capable of receiving and displaying different |
| transformers are steel. Various additives are | | | | video systems like PAL, SECAM and NTSC. |
| made to improve the magnetic properties, as | | | | You'll be able to operate a multisystem TV in |
| for example the magnetic permeability. The | | | | 99% of the world. Their dual voltage design |
| degree of magnetisation of a material | | | | allows them to be plugged into either a 110 |
| required for a linear response to an applied | | | | voltage source or a 220 voltage source. In |
| magnetic field is termed as | | | | some cases, the plug on the television will |
| Permeability.Ferrite - This is used to get a | | | | not fit your country's outlet, so an |
| very high degree of permeability and | | | | inexpensive plug-adapter will be needed. They |
| excellent high frequency performance.Etc.The | | | | can generally be picked up at an electronics |
| converter and the transformer are both | | | | store such as for $1.95. With a multisystem |
| electric conversion products, that enables | | | | TV, such as a plasma, CRT tube type, LCD or |
| you to run electric devices in foreign lands. | | | | DLP, you'll likely need a codefree (sometimes |
| As discussed earlier, if your electric device | | | | called region free) DVD player. These exist |
| requires 110 Volts AC to run, you will need a | | | | in many forms. When used with a PAL-NTSC TV |
| transformer to step up the 220 volts AC | | | | you'll be able to see the full 625 lines of |
| supply voltage to 110 Volts AC before you can | | | | resolution available in the PAL system and |
| switch on that device that you have.What is | | | | the full 525 lines used in the USA NTSC |
| the difference between a converter and a | | | | system. There exists a converting type of DVD |
| transformer? If the device you are going to | | | | player which is codefree in that it can read |
| operate is a high power heating element or | | | | all of the world's 6 regions and both |
| mechanical motor such as a hair dryer or | | | | standards, PAL and NTSC. 140,000 other |
| iron, you will need a converter to run those | | | | products are available here: Tel. |
| appliances. But if your device is a computer, | | | | |