How to hard reset samsung galaxy mobile phones

Hard reset means to reset your phone to the settings and features which were accompanied from the company or at firmware update instant.

Samsung Galaxy, whether Spica or i7500, is very easy to reset! Firstly just power off the mobile phone, restart it by holding volume down + call + end call. Then it will take you to recovery screen where you can switch to home tab for factory reset.

Another simplest way to achieve hard reset is entering *2767*3855# in dialpad and hit dial! this will help definitely!

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Zener Diode

It is a reverse bias heavily doped P-N junction diode which is made from Silicon and Germanium semiconductor mainly. It is operated in the breakdown region where current is limited by both external resistance and power dissipation of the diode. Zener diode made from Silicon is prefer to Germanium because of its higher temperature and current capability.

Uses/application of Zener Diode:-

1. Zener diode is used as voltage regulator.

2. Zener diode is used as peak differ.

3. Zener diode is used for calibrating volt meters.

4. Zener diode is used for metal protection against damaged from accidental applications of excessive voltage.

 

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Light Emitting Diode(LED)

Light Emitting Diode (LED) is a forward biased PN junctions which emits visible lights when energized. It emits low light when reverse biased and if operated in the reverse direction, the LED will be quickly destroyed.

The construction of a light emitting diode is very different from that of a normal signal diode. The PN junction of an LED is surrounded by a transparent, hard plastic epoxy resign hemispherical shaped shell or body which protects the LED from both vibration and shock. Surprisingly, an LED junction does not actually emit that much light so the epoxy resin body is constructed in such a way that the photons of light emitted by the junction are reflected away from the surrounding substrate base to which the diode is attached and are focused upwards through the domed top of the LED, which itself acts like a lens concentrating the amount of light. This is why the emitted light appears to be brightest at the top of the LED.

Application of LED:-

1. LED are used in burglar alarm system.

2. LED are used for the solid state video display which are rapidly replacing Cathode Ray Tube(CRT).

3. LED are used for numerical displays in pocket calculators.

4. LED are used for displaying alpha-numeric or supplying input powers to lasers for entering information into optical computer memories.

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PN Junction Diode

A PN junction diode is formed by combining a P type semiconductor with N type semiconductor. It has the property of offering a low resistance to current flow in one direction and is the main components used in rectifying circuits. PN junction diodes are mainly manufactured using Germanium or Silicon semiconductor material.

Summary of Junction Diode

The PN junction region of a Junction Diode has the following important characteristics:

1). Semiconductors contain two types of mobile charge carriers, Holes and Electrons.

2). The holes are positively charged while the electrons negatively charged.

3). A semiconductor may be doped with donor impurities such as Antimony (N-type doping), so that it contains mobile charges which are primarily electrons.

4). A semiconductor may be doped with acceptor impurities such as Boron (P-type doping), so that it contains mobile charges which are mainly holes.

5). The junction region itself has no charge carriers and is known as the depletion region.

6). The junction (depletion) region has a physical thickness that varies with the applied voltage.

7). When a diode is Zero Biased no external energy source is applied and a natural Potential Barrier is developed across a depletion layer which is approximately 0.5 to 0.7v for silicon diodes and approximately 0.3 of a volt for germanium diodes.

8). When a junction diode is Forward Biased the thickness of the depletion region reduces and the diode acts like a short circuit allowing full current to flow.

9). When a junction diode is Reverse Biased the thickness of the depletion region increases and the diode acts like an open circuit blocking any current flow, (only a very small leakage current).

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Facebook photo sawn kual dan

Facebook a kan thlalak upload te hi Album ah emaw, mahni duhna hmunah a move kual ve zel theih thin a. A tihdan i la hrelo anih chuan hetiang hian ti ve rawh le.

I profile ah lut hmasa phawt la, chuan photos tih kha i select dawn nia.

A hnuaia mi ang hi a lo lang anga. I thlalak dahsawn duh awmna album kha i select dawn nia. Thlalak ah click lovin Album name ah khan i click dawn nia.

I click zawh hnu chuan a hnuai ami ang hi a lo lang anga, Edit Album tih ah khan i click leh dawn nia.

A hnuai ami ang hian a lo lang leh anga, thlalak dinglam sir kil a arrow ah khan click la, move to other album tih kha i click dawn nia.

A hnuai a a lem ang hian a lo lang anga, i dah duhna album hming kha select la, a bak chu OK click vek ani tawh mai.

He thil hi mobile atang chuan a la tih ve theih loh.

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Generator V/S Inverter

GENERATOR

Generator generates a lot of noise during its operation.

Normally, generators do not have automatic start/stop function. When the mains AC fails, one has to manually start the generator and when the mains return, one need to manually shut down the generator and switch the power supply back from generator to mains.

Starting the generator is a process which requires some force. An old or sick person may not be able to start the generator. Currently some generators are coming with starting switch. By pressing this switch, one can start the generator.

But, this additions makes the generator cost very high and after some time, this starting arrangement start giving trouble. Also, after starting the generator, switching of output supply from mains to generator and back from generator to mains needs to be done manually.

Generator require petrol, diesel, kerosene, etc. for its operation. These are highly inflammable products and generates bad smell in the area. Also during its operation it emits smoke which could be harmful to the people around it.
As generator has many mechanical parts, it requires constant maintenance, also the carburetor etc of the generator requires constant maintenance.

INVERTER
Inverter works noiselessly.
Inverters provided completely automatic switch over function. When the mains supply fails, the inverter immediately switches the output to its internal battery and when the mains supply returns, the inverter shuts down its operation and provides the mains AC supply at its output.
Inverter does not require any special starting process and the switching of output from mains to inverter and inverter to mains is done automatically.
Inverter works on battery, which works noiselessly without producing any smell or harmful emissions etc.
As the inverter is an electrical device it does not require any special maintenance. Only the battery used with the inverter will require some routine service such as topping it with distill water once in 15-20 days.

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Properties of the sound waves

Post hmasa lamah sound chungchang kan sawi tawh a. We shall now take a look at some of the properties of the sound waves.

Frequency

Frequency of a sound wave is the number of vibrations done by the sound wave in one second. The frequency is represented by cycles per second (C/S) or by Hertz. If the number of vibrations of sound wave is 100 vibrations per seconds then it is said to be a sound wave with 100 C/S or 100 Hertz(Hz) frequency. Frequency of 1000 C/S is commonly called 1KC/S or 1 kilo hertz.

Lower frequency sound will have more bass and as the frequency increases the sound become shriller. A female voice contain more high frequency sound than a male voice, male voice has more low frequency sound.

Human ear can detect frequencies from 20Hz to 20,000Hz, this range of frequency is known as "Audible Frequency". The higher and lower end of audible sound is heard only by people having sensitive ear such as children; older people find it difficult to hear the lower and higher end of frequencies.

Sound wave with frequency higher than highest audible frequency (20,000Hz) is called "Ultrasonic Wave" and waves with lower than the lowest audible frequency (20Hz) is called "Infrasonic Wave".

Intensity

Intensity is the loudness of the sound. A louder sound will have more intensity compared to a weak sound.

The sound intensity ratio is represented by "Decibel". This unit decibel(dB) is the 10th part of another unit "Bell", which is based on the name of the father of telephone - Graham Bell.

The decibel is logarithmic system of showing power ratio and is used extensively. Power of ratio of 10:1 is equal to 10 decibels (dBs) and that of 100:1 is 20 decibels (dBs).

Echo

Echo is another property of the sound waves. As the light wave get reflected from a mirror, the sound wave also gets reflected when it hits some obstacle. After hitting the obstacle the sound wave returns and the angle with which sound wave strike the obstacle.

Depending on the distance of the obstacle, this property of sound makes us hear the same sound twice or more than twice. This sound which has come back after hitting some obstacle is called an echo.

To get a clear echo the area of reflective block should be very large, and the interval between the direct sound and the reflected sound should be 1/15th of a second or more. Also the length of sound should be small.

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