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[[Image:2007-09-02 CCFL lamp driver.jpg|200px|thumb|right|Conventional CCFL inverter]]
It is very common to have a dental emergency -- a fractured tooth, an abscess, or severe pain when chewing. Over-the-counter pain medication is just masking the problem. Seeing an emergency dentist is critical to getting the source of the problem diagnosed and corrected as soon as possible.<br><br>Here are some common dental emergencies:<br>Toothache: The most common dental emergency. This generally means a badly decayed tooth. As the pain affects the tooth's nerve, treatment involves gently removing any debris lodged in the cavity being careful not to poke deep as this will cause severe pain if the nerve is touched. Next rinse vigorously with warm water. Then soak a small piece of cotton in oil of cloves and insert it in the cavity. This will give temporary relief until a dentist can be reached.<br><br>At times the pain may have a more obscure location such as decay under an old filling. As this can be only corrected by a dentist there are two things you can do to help the pain. Administer a pain pill (aspirin or some other analgesic) internally or dissolve a tablet in a half glass (4 oz) of warm water holding it in the mouth for several minutes before spitting it out. DO NOT PLACE A WHOLE TABLET OR ANY PART OF IT IN THE TOOTH OR AGAINST THE SOFT GUM TISSUE AS IT WILL RESULT IN A NASTY BURN.<br><br>Swollen Jaw: This may be caused by several conditions the most probable being an abscessed tooth. In any case the treatment should be to reduce pain and swelling. An ice pack held on the outside of the jaw, (ten minutes on and ten minutes off) will take care of both. If this does not control the pain, an analgesic tablet can be given every four hours.<br><br>Other Oral Injuries: Broken teeth, cut lips, bitten tongue or lips if severe means a trip to a dentist as soon as possible. In the mean time rinse the mouth with warm water and place cold compression the face opposite the injury. If there is a lot of bleeding, apply direct pressure to the bleeding area. If bleeding does not stop get patient to the emergency room of a hospital as stitches may be necessary.<br><br>Prolonged Bleeding Following Extraction: Place a gauze pad or better still a moistened tea bag over the socket and have the patient bite down gently on it for 30 to 45 minutes. The tannic acid in the tea seeps into the tissues and often helps stop the bleeding. If bleeding continues after two hours, call the dentist or take patient to the emergency room of the nearest hospital.<br><br>Broken Jaw: If you suspect the patient's jaw is broken, bring the upper and lower teeth together. Put a necktie, handkerchief or towel under the chin, tying it over the head to immobilize the jaw until you can get the patient to a dentist or the emergency room of a hospital.<br><br>Painful Erupting Tooth: In young children teething pain can come from a loose baby tooth or from an erupting permanent tooth. Some relief can be given by crushing a little ice and wrapping it in gauze or a clean piece of cloth and putting it directly on the tooth or gum tissue where it hurts. The numbing effect of the cold, along with an appropriate dose of aspirin, usually provides temporary relief.<br><br>In young adults, an erupting 3rd molar (Wisdom tooth), especially if it is impacted, can cause the jaw to swell and be quite painful. Often the gum around the tooth will show signs of infection. Temporary relief can be had by giving aspirin or some other painkiller and by dissolving an aspirin in half a glass of warm water and holding this solution in the mouth over the sore gum. AGAIN DO NOT PLACE A TABLET DIRECTLY OVER THE GUM OR CHEEK OR USE THE ASPIRIN SOLUTION ANY STRONGER THAN RECOMMENDED TO PREVENT BURNING THE TISSUE. The swelling of the jaw can be reduced by using an ice pack on the outside of the face at intervals of ten minutes on and ten minutes off.<br><br>If you liked this short article and you would like to obtain more details with regards to [http://www.youtube.com/watch?v=90z1mmiwNS8 dentist DC] kindly stop by our web site.
 
A '''CCFL inverter''' is an [[electrical inverter]] that supplies [[alternating current]] power to a [[cold cathode fluorescent lamp]] (CCFL). CCFLs are often used as inexpensive light units in electrical devices powered by [[direct current]], such as [[electrical battery|batteries]].  CCFL inverters are small, have switchover efficiency over 80%, and offer adjustable output of light.  They are widely used for backlights for [[LCD]]s, or for rear lighting in advertising signs.
 
[[Image:CCFL Inverter.jpg|350px|thumb|Example of the advanced CCFL Inverter for notebook]]
[[Image:Micro Tesla Coil 2.JPG|150px|thumb|Resonance transformer and ultra-small CCFL-Inverter]]
 
==History of the Technology==
[[Image:CCFL Inverter Circuit1.gif|200px|thumb|CCFL Inverter circuit of the past generation of technology]]
[[Image:CCFL Inverter Circuit2.gif|200px|thumb| CCFL Inverter circuit of the advanced technology]]
[[Image:CCFL Inverter Circuit3.gif|200px|thumb| CCFL Inverter circuit of the most advanced technology]]
 
As for the inverter circuit of a cold cathode fluorescent lamp, a resonance type circuit has been widely used. This is sometimes referred to as the "[[royer oscillator|Royer circuit]]". However the proper definition of the Royer circuit requires that the inversion of a switching operation be performed in a state in which the transformer is saturated. An inverter circuit which performs the inversion operation by utilizing resonance in the collector circuit of a transistor is preferably referred to as the "[[collector resonance circuit|collector resonance type circuit]]" or the "collector resonance type Royer circuit" in distinction from a true Royer circuit.<ref>[http://www.google.com/patents?id=ZxEaAAAAEBAJ&pg=PA1&source=gbs_selected_pages&cad=2#v=onepage&q&f=false Royer Oscillator Circuit United States Patent 2783384]</ref>
 
The early designs of an inverter circuit for a cold cathode fluorescent lamp did not utilize the resonance method of a secondary circuit at all. Instead the so-called closed magnetic circuit type transformer having a small leakage inductance was used as a step-up transformer. The leakage inductance was such that it reduced the output voltage on the secondary side of the transformer. Since this was not desirable, it had to be made as small as possible.
 
Because the resonant frequency of the secondary side circuit of the transformer in the early designs was decided to have no relation with the operating frequency of the inverter circuit, the resonant frequency was set to a much higher frequency than that of the inverter circuit. This greatly reduces the influence of the inverter circuit on the operating frequency. A ballast capacitor Cb is essential for stabilization of the lamp current.
 
Another design for the inverter circuit of a cold cathode fluorescent lamp is shown in the figure of the “CCFL Inverter circuit of the past generation of technology“. It isn't used any more.
 
The more recent inverter circuit was invented by Hitachi electronics in Japan. It has come into world wide use as the so-called three-times or third harmonic resonance circuit, shown in the figure as the “advanced technology“. The resonance frequency of the secondary side circuit is three times that of the primary side. A step-up transformer with a greater leakage inductance value is suitable for use in this case.
 
The transformer which is actually used in the so-called three-times resonance circuit has a flat shape. Although the magnetic path structure is closed, the leakage of the magnetic flux is considerably more than that of the conventional type. The transformer therefore has a larger leakage inductance value. The design (refer to figure of the “past generation of technology“) is such that the leakage inductance value of the step-up transformer is increased to some degree, whereby a resonance circuit is created by the leakage inductance (Lsc in the figures) and a capacitance component obtained on the secondary side of the step-up transformer. The resonance frequency of the circuit is set to a frequency three times as high as the operating frequency of the inverter circuit in order to generate a third-order harmonic in the secondary side circuit. The lamp current waveform has a trapezoid shape. The ballast capacitor Crb also functions as a resonance capacitor. As a result the conversion efficiency of the inverter circuit is considerably improved, and the step-up transformer is further miniaturized.
 
In the most recent circuit design shown, both the primary and secondary sides of the circuit operate at close to the same fundamental frequency. This began to be widely implemented in about 1996, and has greatly contributed to the miniaturization and higher efficiency of the inverter circuit used in a notebook type personal computer.
 
:<math>f_o = \frac{1}{2 \pi \sqrt{L_p \cdot C_o}} \approx \frac{1}{2 \pi \sqrt{L_\mathrm{sc} \cdot (C_w + C_a + C_s)}}</math>
 
The leakage inductance value of the step-up transformer is further increased from that of the three-times resonance design. The capacitance component of the secondary side circuit is also increased.
 
[[Image:Current Resonant CCFL Inverter.gif||200px|thumb|Current Resonant Inverter circuit for the CCFL lighting]]
The next generation's inverter technology for the CCFL Lighting is the [[Resonant inverter|current resonance]] type inverter circuit. The resonance current which causes at the secondary side of the transformer is directly switching the primary side of the transformer through the switching transistor.  
It simplifies the circuit and improves efficiency.
 
==See also==
* [[Royer oscillator]]
 
==External links==
# [http://repair-notebook.com/2009/04/22/%e0%b8%ab%e0%b8%a5%e0%b8%ad%e0%b8%94-backlight-ccfl%e0%b8%82%e0%b8%ad%e0%b8%87-notebook/ Notebook Inverter Schematic]
# [[Jim Williams (analog designer)|Jim Williams]], [http://cds.linear.com/docs/Application%20Note/an65f.pdf "A fourth generation of LCD backlight technology: Component and measurement improvements refine performance"], Linear Technology Application Note 65, November 1995.
# [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7,541,749.PN.&OS=PN/7,541,749&RS=PN/7,541,749 Descriptions of the history of the CCFL inverter and Current resonant Inverter for the CCFL lighting.]
 
==References==
<references/>
 
[[Category:Electrical power conversion]]

Latest revision as of 01:03, 15 November 2014

It is very common to have a dental emergency -- a fractured tooth, an abscess, or severe pain when chewing. Over-the-counter pain medication is just masking the problem. Seeing an emergency dentist is critical to getting the source of the problem diagnosed and corrected as soon as possible.

Here are some common dental emergencies:
Toothache: The most common dental emergency. This generally means a badly decayed tooth. As the pain affects the tooth's nerve, treatment involves gently removing any debris lodged in the cavity being careful not to poke deep as this will cause severe pain if the nerve is touched. Next rinse vigorously with warm water. Then soak a small piece of cotton in oil of cloves and insert it in the cavity. This will give temporary relief until a dentist can be reached.

At times the pain may have a more obscure location such as decay under an old filling. As this can be only corrected by a dentist there are two things you can do to help the pain. Administer a pain pill (aspirin or some other analgesic) internally or dissolve a tablet in a half glass (4 oz) of warm water holding it in the mouth for several minutes before spitting it out. DO NOT PLACE A WHOLE TABLET OR ANY PART OF IT IN THE TOOTH OR AGAINST THE SOFT GUM TISSUE AS IT WILL RESULT IN A NASTY BURN.

Swollen Jaw: This may be caused by several conditions the most probable being an abscessed tooth. In any case the treatment should be to reduce pain and swelling. An ice pack held on the outside of the jaw, (ten minutes on and ten minutes off) will take care of both. If this does not control the pain, an analgesic tablet can be given every four hours.

Other Oral Injuries: Broken teeth, cut lips, bitten tongue or lips if severe means a trip to a dentist as soon as possible. In the mean time rinse the mouth with warm water and place cold compression the face opposite the injury. If there is a lot of bleeding, apply direct pressure to the bleeding area. If bleeding does not stop get patient to the emergency room of a hospital as stitches may be necessary.

Prolonged Bleeding Following Extraction: Place a gauze pad or better still a moistened tea bag over the socket and have the patient bite down gently on it for 30 to 45 minutes. The tannic acid in the tea seeps into the tissues and often helps stop the bleeding. If bleeding continues after two hours, call the dentist or take patient to the emergency room of the nearest hospital.

Broken Jaw: If you suspect the patient's jaw is broken, bring the upper and lower teeth together. Put a necktie, handkerchief or towel under the chin, tying it over the head to immobilize the jaw until you can get the patient to a dentist or the emergency room of a hospital.

Painful Erupting Tooth: In young children teething pain can come from a loose baby tooth or from an erupting permanent tooth. Some relief can be given by crushing a little ice and wrapping it in gauze or a clean piece of cloth and putting it directly on the tooth or gum tissue where it hurts. The numbing effect of the cold, along with an appropriate dose of aspirin, usually provides temporary relief.

In young adults, an erupting 3rd molar (Wisdom tooth), especially if it is impacted, can cause the jaw to swell and be quite painful. Often the gum around the tooth will show signs of infection. Temporary relief can be had by giving aspirin or some other painkiller and by dissolving an aspirin in half a glass of warm water and holding this solution in the mouth over the sore gum. AGAIN DO NOT PLACE A TABLET DIRECTLY OVER THE GUM OR CHEEK OR USE THE ASPIRIN SOLUTION ANY STRONGER THAN RECOMMENDED TO PREVENT BURNING THE TISSUE. The swelling of the jaw can be reduced by using an ice pack on the outside of the face at intervals of ten minutes on and ten minutes off.

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