Wednesday 25 January 2012

About super capacitor


                                  Super capacitor

Super capacitor is an advance version of the conventional electrolytic capacitor. It is also known as the ultra capacitor, electric double layer capacitor or electrochemical double layer capacitor. It is a special type capacitor that has high energy density and this energy density is usually hundreds of times greater than conventional electrolytic capacitors. It also has a much higher power density than batteries or fuel cells. Super capacitor is used for energy storage rather than as general-purpose circuit components. It has a variety of commercial applications, notably in "energy smoothing" and momentary-load devices. Ultra capacitor also has applications as energy-storage because it can quickly charge. Due to same reason, it is extremely essential for domestic solar energy system.
Series connected super capacitor

Voltage increased by series connection of Ultra capacitor

Basic idea:
Conventional capacitor has two metallic plates which are separated by insulation. When a voltage source connects with capacitor, then charges flow through capacitor and capacitor is charged. In this way a potential difference creates within two plates of capacitor. There is used a dielectric material between the plates. Voltage of capacitor can be controlled by dielectric, but ultra capacitor can not be controlled by conventional dielectric.

Electric double layer capacitor also has two metal plates which are coated with activated carbon and separated by an intervening insulator. It uses virtual plates which are in fact two layers of the identical substrate. Due to its electrochemical properties, it is called electrical double layer. It has two electrodes positive and negative. Capacitor capacitance can be increased by increasing surface area of each electrode or decreasing distance between electrodes. As a result, stored energy of the capacitor, which directly proportional to capacitance, also increases. Super capacitor has two electrodes with much higher areas and much thinner dielectrics. These dielectrics decrease the distance between two electrodes. These implementations help to increase capacitance and stored energy in super capacitor.



Super capacitor has low voltage, but it can be increased by series combination of matched super capacitors. Ultra capacitor has much higher power density than batteries. If power density is high, energy will quickly deliver to the load (electronic equipments).Movement of charge is slow in Batteries means power density is low than super capacitors. So, batteries delivery speed of charge is slow and charge discharge time also relatively slow. 

  

Applications:
Some electric vehicle manufacturers are using ultra capacitors for acceleration. Super capacitor also appears in hundreds of other applications, from cell phone base stations to alarm clocks (as backup power) to audio systems. Ultra capacitor is also used in electric power grid. When transmission lines operate below full capacity, Ultra capacitors banks could be set up to absorb power surges and enable transmission lines to activate near to 100% capacity.

Super capacitor is used in vehicle for acceleration 

Advantages:
Super capacitor has low cost per cycle, good reversibility, very high rates of charging and discharging ability. It also has high output power. It can be used in simple charging method. It is free from overcharging and need not any full-charge detection. 

Electrochemical double layer capacitor


 



Monday 23 January 2012

Water compressed technology


                                           Water will be used as car fuel

A Bangladeshi named MD.Zoinal Abedin Jasim declares that he has invented alternative automobile car fuel which is compressed water technology. He said that if this technology is used, world fuel cost will be reduced from 80 to 90 percent. By using this technique, an automobile car can pass nine hundred kilometer distance. Main formula of this technology is to separate the oxygen and hydrogen gas from water, then hydrogen will be used as fuel for the car engine. Inventor also said that, normally a car takes one liter oil for passing 10 to 12 km distance, but only 5 to 7 percent of water of this new technology can be used for same car to overcome 40 to 50 km distance. Jasim said that installation cost of the compressed water system on car will be approximately ten thousand taka (Bangladeshi money) or 122-US$.New compressed water method connected car will easily overcome nine hundred km by using only 1.5 liter water.

Water compressed system

Water compressed car
Inventor name: MD.Zoinal Abedin Jasim

Location:Nowapara,Rawzan,Chittagong,Bangladesh

News source: THE DAILY ITTEFAQ,Bangladesh            

Saturday 21 January 2012

LED TV Vs LCD TV


                                                 LED TV is better than LCD TV









LED means Light Emitting Diodes and LCD means Liquid Crystal Display. LED is an advance technology of LCD and LED is better than LCD for some technical reasons. They are given below

1st reason (Quality of color patterns): LED TVs display more precise color than LCD TVs. As a result LED TVs are capable of showing natural color to the viewers. A series of light emitting diodes is connected with each other at the edges of the LED screen. This series connection works as a filter for displaying accurate color of the viewing objects.

2nd reason (Contrast levels and dark area): The contrast percentage of LED TVs is much better than LCD TVs. This is why LED TVs create better dark area of the picture, but LCD TVs can not do this.

3rd reason (Viewing angle): Viewers can watch LED TV in unlimited viewing angles without diminishing the quality of the picture, but the viewing angle of LCD TV is 30 degrees that is major difference between LCD and LED TV. Spectators can not watch the pure picture quality of LCD TV without fixed 30 degrees viewing angle.

4th reason(Power consumption):People want to get less electricity bill which can be provided by the LED TV.LED TV consumes less electric power than LCD TV. This is an another great advantage of the LED TV over the LCD TV.

5th reason (Size): LED TV’s screen size range is 17 inches  to 70 inches whereas the LCD TVs range is between 15 inches to 65 inches.         

Briefly, we can say LED TVs have following advantages over the LCD TVs
1.     High quality of color patterns.
2.     Better contrast levels and dark area of picture.
3.     Unlimited viewing angles
4.     Less power consumption
5.     Bigger screen size 





About Superconductor


Super Conductor

A conductor has a resistance that creates power loss, but super conductor has no resistance in a critical temperature. Generally, resistance is a power loss factor in a conductor, which is undesirable. We know that from Ohm’s law I=V/R where, I=Flow of electricity,V=Voltage difference between two points,R=Resistance of the particular material.
If  R=0, I=V/0=infinitive, so power loss(I*I*R=0) in super conductor will be zero.

Heike Kamerlingh Onnes discovered superconductivity on April 8,1911 in Leiden.He cooled a material to the temperature of liquid helium(-269C),he found that its resistance suddenly vanished or zero.In 1913,He won a Nobel Prize in physics for his research on superconductivity. Specific conductor will be converted into super conductor with zero resistance .Magnetic field can not enter to the inner portion of a super conductor (Transition of superconducting state). It refers to quantum mechanical phenomenon.


THE Meissner Effect: When a material converts to normal conductor to super conductor (transitional state),it actively throw-outs magnetic fields from its interior, this phenomenon is called Meissner effect. 

Arrow signed line is magnetic field line.






 USE OF SUPERCONDUCTORS: 
1.      Superconductor has a magnetic-levitation character. Modern train can run on float area without any friction between the train and its tracks.It can be made by superconducting magnets. From this application, Japan commercially used Magnetic-levitation technology in 1990.The MLX01 test train gained an incredible speed of 361 mph(581 Kilometer per hour) in December 2003)



2. In biomegnetism field, superconductor is used as a life-saving function .Doctors need to know that what’s going on inside the human body. MRI(Magnetic Resonance Imaging) is made by a strong superconductor-derived magnetic field.when a strong superconductor –derived magnetic field,which forcedly give energy to hydrogen atoms that exist in body's water and fat molecules, apply into body .Then they  release given energy at a particular frequency which can be identified and showed graphically by a computer.  

MRI of a human skull.