Wednesday, June 22, 2011

Cotrage refiling

Now you can easly refill your cotrage by following video help
Thanks

Cotrage refiling

I love Pakistan


The geography of Pakistan (Urduجغرافیہ پاکِستان) is a profound blend of landscapes varying from plains to deserts, forests, hills, and plateaus ranging from the coastal areas of the Arabian Sea in the south to the mountains of the Karakoram range in the north. Pakistan geologically overlaps both with the Indian and the Eurasian tectonic plateswhere its Sindh and Punjab provinces lie on the north-western corner of the Indian plate while Balochistan and most of the Khyber-Pakhtunkhwa lie within the Eurasian plate which mainly comprises the Iranian plateau, some parts of the Middle East and Central Asia. The Northern Areas and Azad Kashmir lie mainly in Central Asia along the edge of the Indian plate and hence are prone to violent earthquakes where the two tectonic plates collide.
Pakistan is bordered by Afghanistan to the north-west and Iran to the west while thePeople's Republic of China borders the country in the north and India to the east. The nation is geopolitically placed within some of the most controversial regional boundaries which share disputes and have many-a-times escalated military tensions between the nations, e.g., that of Kashmir with India and the Durand Line with Afghanistan. Its western borders include the Khyber Pass and Bolan Pass that have served as traditional migration routes between Central Eurasia and South Asia.

Friday, November 26, 2010

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Friday, October 8, 2010

INCREASE HEIGHT



Increase your height with in 4 weeks
Here some tips are given to increase your height because,
. People try many different ways like medicine, acupressure treatments etc. to
gain height; but these all are very expensive and doubtful ways and there is no
100% assurance whether it will work or not. The best way to gain height is to do
some exercises to increase height.
i) Stand in an open space in attention position.
In hale deeply through the nose and extend yours arms lifting then slowly up to
your shoulders. Keep your arms straight. Hold that position for

some time and then take the arms backwards as far as they will go. No inhale
again the release your breath slowly, resuming the former position.
(ii) Stand with your arms straight at right
angles to your body. Lift the arms vertically and then bring them to the level
of the shoulders. Do not exhale in the process, but stand on your toes, lifting
your heels as far as they will go. Exhale slowly after some moments and resume
the earlier position.
(iii) Extend your arms forward up to the level of
the shoulders. Inhale and fill your lungs to about one-third of their capacity.
Wait for a few moments and then take your arms above your head. Now move them in
a circular motion-taking them behind your back and in the former position again.
Exhale slowly.
How can one increase weight?

Take to a diet for three to four days. Take 100 to 150 grams of bran with the
fruits. The best way will be to mix bran with a fruit like papaya. It will
increase appetite, improve the digestion and remove costiveness, if any. One
will tend to eat more and the capacity to assimilate food will be increased.
Foods like flour, rice honey, raisins, figs,
dates, butter, and etc. can help increase weight. Sweat substances can increase
weight than fatty foods. Those wishing to increase their weight should become
pure vegetarians and eat fruits, rice, flour, fresh vegetables, bananas, dry
fruits, butter, and milk. Germinated wheat is also extremely beneficial if taken
in the form of gruel mixed with hot

milk.
Take plenty of water, exercise and fast once a week

Tuesday, September 21, 2010

hazard of mobile fone

There are several different types of radiation present in our surroundings on a day to day basis. Electromagnetic energy from cell phones and radio towers are categorized as non-ionizing radiation and are generally thought to be harmless, while iodizing rays from x-rays and nuclear energy have been proven to cause cancer.
However, in recent years the sheer number of non-ionizing instruments in our environment has caused some scientists to wonder if the assumption that this type of radiation is truly safe.
The technological benefits of Wireless Fidelity technology versus the wireless hazards is a hot debate in many different countries. In the United States, a class action lawsuit has been brought against a school board who use the technology in their classrooms. In Britain, it has been removed from some classrooms altogether. Are these precautionary measures necessary, or simply the reaction of a public frightened by a technology they do not fully understand?

A new study released by the Reproductive Research Centre at the Cleveland Clinic in Ohio suggests an alarming increase in infertility amongst men who frequently use cell phones. In each of the four criteria singled out in the study sperm count, motility, viability and appearance those who used cell phones more than four hours per day fared the worst in each category.
The study, led by Professor Ashok Agarwal, divided over 360 men into three categories: those who never used a cell phone, those who used a cell phone less than two hours per day and the final group of men, who used their cell phones at least four hours each day. 

Rectifier


rectifier is an electrical device that converts alternating current (AC), current that periodically reverses direction, to direct current (DC), current that flows in only one direction, a process known as rectification. Rectifiers have many uses including as components of power supplies and as detectors of radio signals. Rectifiers may be made of solid state diodesvacuum tube diodes, mercury arc valves, and other components.
A device which performs the opposite function (converting DC to AC) is known as an inverter.
When only one diode is used to rectify AC (by blocking the negative or positive portion of the waveform), the difference between the termdiode and the term rectifier is merely one of usage, i.e., the term rectifier describes a diode that is being used to convert AC to DC. Almost all rectifiers comprise a number of diodes in a specific arrangement for more efficiently converting AC to DC than is possible with only one diode. Before the development of silicon semiconductor rectifiers, vacuum tube diodes and copper(I) oxide or selenium rectifier stacks were used.
Early radio receivers, called crystal radios, used a "cat's whisker" of fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-contact rectifier or "crystal detector". Rectification may occasionally serve in roles other than to generate D.C. current per se. For example, in gas heating systems flame rectification is used to detect presence of flame. Two metal electrodes in the outer layer of the flame provide a current path, and rectification of an applied alternating voltage will happen in the plasma, but only while the flame is present to generate it

SemiConductor DIOD

 diode is an electrical device allowing current to move through it in one direction with far greater ease than in the other. The most common kind of diode in modern circuit design is the semiconductor diode, although other diode technologies exist. Semiconductor diodes are symbolized in schematic diagrams such as Figurebelow. The term “diode” is customarily reserved for small signal devices, I ≤ 1 A. The term rectifier is used for power devices, I > 1 A.
Semiconductor diode schematic symbol: Arrows indicate the direction of electron current flow.
When placed in a simple battery-lamp circuit, the diode will either allow or prevent current through the lamp, depending on the polarity of the applied voltage. (Figure below)
Diode operation: (a) Current flow is permitted; the diode is forward biased. (b) Current flow is prohibited; the diode is reversed biased.
When the polarity of the battery is such that electrons are allowed to flow through the diode, the diode is said to be forward-biased. Conversely, when the battery is “backward” and the diode blocks current, the diode is said to be reverse-biased. A diode may be thought of as like a switch: “closed” when forward-biased and “open” when reverse-biased.
Oddly enough, the direction of the diode symbol's “arrowhead” points against the direction of electron flow. This is because the diode symbol was invented by engineers, who predominantly use conventional flownotation in their schematics, showing current as a flow of charge from the positive (+) side of the voltage source to the negative (-). This convention holds true for all semiconductor symbols possessing “arrowheads:” the arrow points in the permitted direction of conventional flow, and against the permitted direction of electron flow.
Diode behavior is analogous to the behavior of a hydraulic device called a check valve. A check valve allows fluid flow through it in only one direction as in Figure below.
Hydraulic check valve analogy: (a) Electron current flow permitted. (b) Current flow prohibited.
Check valves are essentially pressure-operated devices: they open and allow flow if the pressure across them is of the correct “polarity” to open the gate (in the analogy shown, greater fluid pressure on the right than on the left). If the pressure is of the opposite “polarity,” the pressure difference across the check valve will close and hold the gate so that no flow occurs.
Like check valves, diodes are essentially “pressure-” operated (voltage-operated) devices. The essential difference between forward-bias and reverse-bias is the polarity of the voltage dropped across the diode. Let's take a closer look at the simple battery-diode-lamp circuit shown earlier, this time investigating voltage drops across the various components in Figure below.
Diode circuit voltage measurements: (a) Forward biased. (b) Reverse biased.
A forward-biased diode conducts current and drops a small voltage across it, leaving most of the battery voltage dropped across the lamp. If the battery's polarity is reversed, the diode becomes reverse-biased,and drops all of the battery's voltage leaving none for the lamp. If we consider the diode to be a self-actuating switch (closed in the forward-bias mode and open in the reverse-bias mode), this behavior makes sense. The most substantial difference is that the diode drops a lot more voltage when conducting than the average mechanical switch (0.7 volts versus tens of millivolts).
This forward-bias voltage drop exhibited by the diode is due to the action of the depletion region formed by the P-N junction under the influence of an applied voltage. If no voltage applied is across a semiconductor diode, a thin depletion region exists around the region of the P-N junction, preventing current flow. (Figurebelow (a)) The depletion region is almost devoid of available charge carriers, and acts as an insulator:
Diode representations: PN-junction model, schematic symbol, physical part.
The schematic symbol of the diode is shown in Figure above (b) such that the anode (pointing end) corresponds to the P-type semiconductor at (a). The cathode bar, non-pointing end, at (b) corresponds to the N-type material at (a). Also note that the cathode stripe on the physical part (c) corresponds to the cathode on the symbol.
If a reverse-biasing voltage is applied across the P-N junction, this depletion region expands, further resisting any current through it. (Figure below)
Depletion region expands with reverse bias.
Conversely, if a forward-biasing voltage is applied across the P-N junction, the depletion region collapses becoming thinner. The diode becomes less resistive to current through it. In order for a sustained current to go through the diode; though, the depletion region must be fully collapsed by the applied voltage. This takes a certain minimum voltage to accomplish, called the forward voltage as illustrated in Figure below.
Inceasing forward bias from (a) to (b) decreases depletion region thickness.
For silicon diodes, the typical forward voltage is 0.7 volts, nominal. For germanium diodes, the forward voltage is only 0.3 volts. The chemical constituency of the P-N junction comprising the diode accounts for its nominal forward voltage figure, which is why silicon and germanium diodes have such different forward voltages. Forward voltage drop remains approximately constant for a wide range of diode currents, meaning that diode voltage drop is not like that of a resistor or even a normal (closed) switch. For most simplified circuit analysis, the voltage drop across a conducting diode may be considered constant at the nominal figure and not related to the amount of current.
Actually, forward voltage drop is more complex. An equation describes the exact current through a diode, given the voltage dropped across the junction, the temperature of the junction, and several physical constants. It is commonly known as the diode equation:
The term kT/q describes the voltage produced within the P-N junction due to the action of temperature, andis called the thermal voltage, or Vt of the junction. At room temperature, this is about 26 millivolts. Knowing this, and assuming a “nonideality” coefficient of 1, we may simplify the diode equation and re-write it as such:
You need not be familiar with the “diode equation” to analyze simple diode circuits. Just understand that the voltage dropped across a current-conducting diode does change with the amount of current going through it, but that this change is fairly small over a wide range of currents. This is why many textbooks simply say the voltage drop across a conducting, semiconductor diode remains constant at 0.7 volts for silicon and 0.3 volts for germanium. However, some circuits intentionally make use of the P-N junction's inherent exponential current/voltage relationship and thus can only be understood in the context of this equation. Also, since temperature is a factor in the diode equation, a forward-biased P-N junction may also be used as a temperature-sensing device, and thus can only be understood if one has a conceptual grasp on this mathematical relationship.
A reverse-biased diode prevents current from going through it, due to the expanded depletion region. In actuality, a very small amount of current can and does go through a reverse-biased diode, called theleakage current, but it can be ignored for most purposes. The ability of a diode to withstand reverse-bias voltages is limited, as it is for any insulator. If the applied reverse-bias voltage becomes too great, the diode will experience a condition known as breakdown (Figure below), which is usually destructive. A diode's maximum reverse-bias voltage rating is known as the Peak Inverse Voltage, or PIVand may be obtained from the manufacturer. Like forward voltage, the PIV rating of a diode varies with temperature, except that PIV increases with increased temperature and decreases as the diode becomes cooler -- exactly opposite that of forward voltage.
Diode curve: showing knee at 0.7 V forward bias for Si, and reverse breakdown.
Typically, the PIV rating of a generic “rectifier” diode is at least 50 volts at room temperature. Diodes with PIV ratings in the many thousands of volts are available for modest prices.
  • REVIEW:
  • diode is an electrical component acting as a one-way valve for current.
  • When voltage is applied across a diode in such a way that the diode allows current, the diode is said to be forward-biased.
  • When voltage is applied across a diode in such a way that the diode prohibits current, the diode is said to be reverse-biased.
  • The voltage dropped across a conducting, forward-biased diode is called the forward voltage. Forward voltage for a diode varies only slightly for changes in forward current and temperature, andis fixed by the chemical composition of the P-N junction.
  • Silicon diodes have a forward voltage of approximately 0.7 volts.
  • Germanium diodes have a forward voltage of approximately 0.3 volts.
  • The maximum reverse-bias voltage that a diode can withstand without “breaking down” is called thePeak Inverse Voltage, or PIV rating.