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

Singles phase half wave controlled rectifier with rl load, Singles Phase ...

Singles Phase  Half wave Controlled Rectifier  with RL Load When gate pulses are applied to the thyristor  at output voltage  v0 follows the input voltage  v s ( = V m sin ) s

Rankine cycle and modified rankine cycle, Discuss in detail the several ene...

Discuss in detail the several energy resources and their availability. How does a Rankine cycle differ from a modified Rankine cycle? Write down the mathematical expression of m

Explain operation modes of programmable interval timer 8254, Explain modes ...

Explain modes of operation of programmable interval timer 8254. Mode 0 - Interrupt upon terminal count Mode 1 - Programmable one-shot Mode 2 - Rate Generator Mode 3 -

What is the direction of a line of flux, What is the Direction of a line of...

What is the Direction of a line of flux The direction of a line of flux is from the north pole to the south pole on the exterior of the magnet and is then supposed to continue

Explain the tap changing transformers, Explain the Tap Changing Transformer...

Explain the Tap Changing Transformers? This is the most popular form of voltage control at all voltage levels. It is based on changing the turns ratio of the transformer, hence

How is 8255 programmable peripheral interface configured, How is 8255 (Prog...

How is 8255 (Programmable Peripheral Interface) configured if its control registercomprises 9B h.  Ans 9BH => 1001 1011 =>    b6b5=00-> Mode0    b4=0-> Port A as

What are operations performed on data in 8085, What are operations performe...

What are operations performed on data in 8085 The various operations performed are Store 8-bit data Perform arithmetic and logical operations Test for conditio

Show the r’s complement, Q. Show the r’s Complement? Step1- get the (r-...

Q. Show the r’s Complement? Step1- get the (r-1)'s complement Step 2- add 1 to the result ex.            935 10                                     9 9 9

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