Gto - gate turn off, Electrical Engineering

Assignment Help:

GTO ( Gate Turn Off)

GTO stands for gate  turn off  thyristor . it is four layer  PNPN  device. It can be  triggered into conduction like a conventional thyristor  by a pulse of  positive  gate  current.GTO  can be easily turned off by   a negative  gate pulse  of appropriate magnitude. The GTO  is a three terminal devices with  anode cathode  and gate terminals. The basic structure  and symbol of GTO  is shown in figure. The  two way arrow convention on the gate lead  distinguishes the GTO  from an ordinary thyristor . The  need of forced  commutation circuit  because turn off  is achieved by applying  a negative  circuit.

The gate  turn off  thyristor  has highly doped N  spots  in the P layer  at the  anode. The  plus again  indicating high  doping level. The  gate  cathode  structure  is inertdigitated  i e each  electrode is composed  of a large number of narrow  channels  closely located.

 Function  of GTO  except for   turn off  are  same as  those of conventional  thyristors  therefore were mainly describe the turn off operation here. When a GTO  is in the on state the central base regions are filled with holes  supplied from the anode and electrons supplied from the cathode. If  reverse bias is applied to make the gate negative in respect to the cathode part of holes in the p base layer are extracted through  the gate suppressing the  injections of electrons from the cathode. In response to this suppression more hole  current  is extracted through the gate  further suppressing  the electron injection. In  the course of this process the  cathode emitter junction is put  into a reverse bias state entirely GTO turned off.

GTO is  analogy of two  transistors ( PNP and NPN ) as  shown  in figure  suppose that GTO thyrisotr is divided  into npn  transistor Trl  on the cathode  side and pnp transistor  Tr2 on the anode  side and that they are connected as shown  in figure  in this figure the current  amplification factor  of transistor  Trl is called  a and that of transistor  Tr2 a2. If  reverse current  IGQ flows through the gate base current iB at transistor Trl is  reduced when IGQ is increased. The  relationship  between GTO  thyristor  anode current (Ia)  and cathode current  (Ik) is expressed by the followings  equations:

La = Ik + IGQ

A GTO  thyristor  can carry  out the turn off if  an adequate magnitude of reverse bias current  is supplied t the gate. Actually however sheet  resistance exists in the trl base  region making it difficult to turn off the on state current flowing at he emitter junction that is  far from  the gate.

1701_GTO ( Gate Turn Off).PNG

                                                                            figure  Two  transistor analogy of GTO


Related Discussions:- Gto - gate turn off

Electrical circuits, equivalent circuit for transistor using h parameters

equivalent circuit for transistor using h parameters

Service standards and agricultural users, Service standards: The forum...

Service standards: The forum of regulators (constituted through the central government for consistency in regulation in the area of distribution) will decide the basic framewo

Ldax load accumulator indirect instruction , LDAX  Load Accumulator Indire...

LDAX  Load Accumulator Indirect Instruction This instruction is used to copy data  from memory  location pointed by register  pair only  BC or DE  to the accumulator  HL pair

Masking - immediate with accumulator instruction , Masking As we know...

Masking As we know the MASJ is used  to cover  some part  of our  face  which  we want to hide  and to  show  other part of the face  which  we want to show. Similarly  the

Determine frequencies that is in the spectrum analyze, Two sine waves along...

Two sine waves along with periods of 10 ms and 30 ms are added to generate a single waveform. A spectrum analyzer is utilized to examine the frequency contents of the waveform. Wha

Binary coded decimal addition, Q. Binary Coded Decimal Addition Now as ...

Q. Binary Coded Decimal Addition Now as in conventional decimal addition, Binary Coded Decimal addition is performed one decimal digit at a time. What happens when the sum g

E. mechanics, a train weight 5 megaN is taking a slope of 1 in 200 at 45 km...

a train weight 5 megaN is taking a slope of 1 in 200 at 45 kmper hour.the engine put in 100 kw.determine the power to be put in by the engine it the train take the slope up of 1 in

Determine the magnetic force on the current element, Q. Given ¯B = (y ¯ax -...

Q. Given ¯B = (y ¯ax - x ¯ay )/(x 2 + y 2 ) T, determine the magnetic force on the current element Id ¯l = 5 × 0.001¯a A located at (3,4,2).

For sign flag - return instructions, For sign flag  RP ( Return on ...

For sign flag  RP ( Return on Plus ) and RM ( Return on no minus ) Instructions RM returns from the subroutine  to the calling program if sign flag is set  (S=1). The in

Describe the functionalities and the purpose of an equalizer, Question: ...

Question: (a) For a CD quality sound, what is the bit depth used and give the amplitude's levels and the dynamic range of this sound quality (b) In audio technology, the dec

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd