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INTRODUCTION
Solar energy is an attractive energy source for powering portable devices. For some time, it has been widely used in applications like calculators and spacecraft.More recently, solar power is being considered for a much wider range of consumer applications including mobile phone chargers. However, power available from a solar panel is heavily dependent on the operating environment. This includes such things as light intensity, time and location. Therefore, batteries typically are used as energy storage elements. They can be charged when extra power is available from the solar panel, as well as to power the system when the available power from the solar panel is insufficient.
A battery charger is a device used to put energy into a secondary cell or (rechargeable) battery by forcing an electric current through it.
This charger is designed to help the people when they are unable to charge because of no electricity. This circuit describes a solar cell phone charger that uses solar panels. DC voltage is transformed to a mobile phone battery and then charge the battery. It automatically stops charging after the completion.
CONSTRUCTION
COMPONENTS USED
• 2-Series SOLAR PANEL
SOLAR CELL PANEL
Basically, a solar cell comprises a p-n junction in which light energy
(photons) causes electrons and holes to recombine, generating an electric current A solar panel (photovoltaic module or photovoltaic panel) is a packaged interconnected assembly of solar cells, also known asphotovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications.Because a single solar panel can only produce a limited amount of power, many installations contain several panels. This is known as aphotovoltaic array. A photovoltaic installation typically includes an array of solar panels, an inverter, batteries and interconnection wiring. Photovoltaic systems are used for either on- or off-grid applications, and on spacecraft.
Solar Cell Types
Keep in mind these cost and performance tradeoffs when comparing various solar cellmaterials:
Polycrystalline cells are commonly found in outdoor applications and have a spectral sensitivity range of 500nm to 1100nm. They’re in the medium price range and typically offer a 13% power conversion efficiency. They suffer from impurities on the polycrystalline material which degrate cell efficiency over operating time. Many polycrystalline cells degrade by 20% over the first 100 operating hours.
Monocrystalline cells, such as the IXYS Solar Bits used in this circuit, have a spectral sensitivity range from 300 nm (near-ultraviolet) to 1100 nm (near-infrared), which includes visible light (400 to 700 nm). Due to this wide spectral range, they can be used in both indoor and outdoor applications. Monocrystalline or single-crystalline material is the most expensive but it does not contain impurities, and as such the power conversion efficiency does not degrade over operating time. The power conversion efficiency of commercially available monocrystalline cells ranges from 15 to 19%. The surface of these cells is a homogenous dark blue or dark grey.
Finally, Amorphous cells, which work in the spectral range of 300nm to 600nm, are used predominantly indoors in products such as solar powered calculators since they are not sensitive to the upper light spectrum and cannot take advantage of natural sunlight. They offer about 5% power conversion efficiency and are mostly used with ultra low power devices like clocks and electronic calculators. Amorphous cells, like polycrystalline cells, suffer from efficiency degradation.
RESISTOR
A resistor is a component of an electrical circuit that resists the flow of electrical current. A resistor has two terminals across which electricity must pass, and is designed to drop the voltage of the current as it flows from one terminal to the next. A resistor is primarily used to create and maintain a known safe current within an electrical component.
Resistance is measured in ohms, after Ohm's law. This rule states that electrical .resistance is equal to the drop in voltage across the terminals of the resistor divided by the current being applied to the resistor. A high ohm rating indicates a high resistance to current. This rating can be written in a number of different ways depending on the ohm rating. For example, 81R represents 81 ohms, while 81K represents 81,000 ohms.