Switching characteristics, Electrical Engineering

Assignment Help:

Switching Characteristics

Switching  characteristics  of BJT  are shown  in figure. Due  to the presence of internal  capacitances BJT  cannot be  turned  instantly. Initially when base  emitter  voltage  is applied in CE  configuration leakage current  flows.  The collection current  begins  to rise after  some delay  time  and reaches at its  steady state  value. the time  from which  collector  current  starts  rising  to its  steady  state value  known  as rise time. BJT gets turned on in and collector emitter  voltages falls from  its maximum  value  forward voltage drop.

1431_Switching Characteristics.PNG

 

Till the forward  base  current is  maintained the BJT  remains in  on condition. As  the base emitter  voltage  is removed at a time t1 does not change for a  time ( there  its is  storage time in which the charges are removed from the base).  After  this time Ic begins to fall and collector voltage starts rising  for a time tf  ( fall time ) . in  fall time  decreases to leakage current  and voltage  rises  to vcc. Hence the turn off time  of BJT is  t off = ts +  tf. In conduction period of BJT a steady state  current  flows and  forward  voltage  drop  appears across the  collection emitter  junctions.

 


Related Discussions:- Switching characteristics

Resultant force, State and prove parallelogram law of forces and explain i...

State and prove parallelogram law of forces and explain it''s applications

What are the signals used in input control signal, What are the signals use...

What are the signals used in input control signal & output control signal? Input control signal STB (Strobe input) IBF (Input buffer full) INTR(Interrupt request) Ou

Control signals - pins and signals , Control Signals There are two  con...

Control Signals There are two  control  signals and one  special  (ALE) in this  category. All these  signals  are output  signals. RD  (Read  signal ) it is  an active low

Explain television signal transmission, Q. Explain Television signal transm...

Q. Explain Television signal transmission? Television signals in television signal transmission are the electric signals generated by converting visual images through raster (T

Speed control of dc series motor - motor control , Speed Control of DC Seri...

Speed Control of DC Series Motor A half  wave  circuit  for the  speed  control of DC  series motor is  shown in figure and corresponding wave from  is shown  in figure  consis

Need for modulation recognition - software defined radio, Need for Modulati...

Need for Modulation Recognition There are so many communication signals all available with different types of modulation and different frequencies. It is necessary to identify

Oscilloscope probe compensation, Q.   what is oscilloscope probe compensati...

Q.   what is oscilloscope probe compensation and how is it adjusted?  What effects are noted when the compensation is not correctly adjustment? Direct Probe: This probe  is

Sketch the spectrum of a standard am signal, If the message has a spectrum ...

If the message has a spectrum where K and Wf are positive constants, sketch the spectrum of a standard AM signal that uses the message. Comment on the physical signi?cance

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