19-06-2012, 05:44 PM
wireless charging using microwave
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INTRODUCTION
To start with, to know what a spectrum is: when white light is shone through a prism it is separated out into all the colours of the rainbow; this is the visible spectrum. So white light is a mixture of all colours. Black is NOT a colour; it is what you get when all the light is taken away.
Some physicists pretend that light consists of tiny particles which they call photons. They travel at the speed of light (what a surprise).
The speed of light is about 300,000,000 meters per second. When they hit something they might bounce off, go right through or get absorbed. What happens depends a bit on how much energy they have. If they bounce off something and then go into your eye you will "see" the thing they have bounced off. Some things like glass and Perspex will let them go through; these materials are transparent. Black objects absorb the photons so you should not be able to see black things: you will have to think about this one.
These poor old physicists get a little bit confused when they try to explain why some photons go through a leaf, some are reflected, and some are absorbed. They say that it is because they have different amounts of energy.
What is the advantage of wireless charging compare to battery charger?
Wireless methods are always advantageous than cumbersome, untidy wiry networks. You can have a lot of options if the facility of wireless charging of mobile phones is somehow implemented. If you are running out of battery, then what you need to do is just call a number from your phone and your phone will be recharged by packet energy within some time without the need to search for plugging in your phone. What you need to do is turn on your laptop or search for any other laptop or phone users near by and charge your phone by Bluetooth
TYPES OF CHARGINGS:
Simple charger:
• A simple charger works by supplying a constant DC or pulsed DC power source to a battery being charged.
• The simple charger does not alter its output based on time or the charge on the battery.
• This simplicity means that a simple charger is inexpensive, but there is a tradeoff in quality. Typically, a simple charger takes longer to charge a battery to prevent severe over-charging. Even so, a battery left in a simple charger for too long will be weakened or destroyed due to over-charging.
Trickle charger:
A trickle charger is typically a low-current (500–1,500 mA) battery charger. A trickle charger is generally used to charge small capacity batteries (2–30 Ah). These types of battery chargers are also used to maintain larger capacity batteries (> 30 Ah) that are typically found on cars, boats, RVs and other related vehicles. In larger applications, the current of the battery charger is sufficient only to provide a maintenance or trickle current (trickle is commonly the last charging stage of most battery chargers).
Timer-based charger:
Timer chargers were the most common type for high-capacity Ni-Cd cells in the late 1990s. If batteries of lower capacity were charged then they would be overcharged, and if batteries of higher capacity were charged they would be only partly charged. Timer based chargers also had the drawback that charging batteries that were not fully discharged, even if those batteries were of the correct capacity for the particular timed charger, would result in over-charging.
Smart charger:
A "smart charger" should not be confused with a "smart battery". A smart battery is generally defined as one containing some sort of electronic device or "chip" that can communicate with a smart charger about battery characteristics and condition. A smart battery generally requires a smart charger it can communicate with (see Smart Battery Data). A smart charger is defined as a charger that can respond to the condition of a battery, and modify its charging actions accordingly. The intelligent battery charger to not sense that the batteries are actually already fully charged, and continue charging.
Solar charger:
Solar chargers convert light energy into DC current. They are generally portable, but can also be fixed mount. Fixed mount solar chargers are also known as solar panels. Solar panels are often connected to the electrical grid, whereas portable solar chargers are used off-the-grid (i.e. cars, boats, or RVs).
Although portable solar chargers obtain energy from the sun only, they still can (depending on the technology) be used in low light (i.e. cloudy) applications. Portable solar chargers are typically used for trickle charging, although some solar chargers (depending on the wattage), can completely recharge batteries.
Mobile phone charger:
A charging station for various brands of mobile phones.Most mobile phone chargers are not really chargers, only power adapters that provide a power source for the charging circuitry which is almost always contained within the mobile phone.They are notoriously diverse, having a wide variety of DC connector-styles and voltages, most of which are not compatible with other manufacturers' phones or even different models of phones from a single manufacturer. A way to charge all your electronic accessories is with a Chargebox.
Charging Rates:
Charge rate is often denoted as C or C-rate and signifies a charge or discharge rate equal to the capacity of a battery in one hour.[14] For a 1.6Ah battery, C = 1.6A. A charge rate of C/2 = 0.8A would need two hours, and a charge rate of 2C = 3.2A would need 30 minutes to fully charge the battery from an empty state, if supported by the battery. This also assumes that the battery is 100% efficient at absorbing the charge.