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

What is an oscillator and show the advantages of oscillators, Q. What is an...

Q. What is an oscillator? Discuss the advantages of Oscillators ? An oscillator is a system consisting of active and passive circuit elements to produce a sinusoidal or other r

Determine the resistivity of the wire, The resistance of 1.5 km of wire of ...

The resistance of 1.5 km of wire of cross-sectional area 0.17 mm 2 is 150Ω. Determine the resistivity of the wire.

What do you mean by frequency response, Q. What do you mean by Frequency Re...

Q. What do you mean by Frequency Response? As with all electronic circuits, op amps have limited frequency response. Because of the negative feedback of the circuit, the passba

Determine phase - voltage and power, Determine phase - voltage and power: ...

Determine phase - voltage and power: A balanced star connected load is supplied from a symmetrical 3-phase 440 Volt system. The current in each of the phase is 40 Amp and lags

The a.c/d.c. generator - electromagnetic torque, Note, the armature curren...

Note, the armature current is produced in pulses as the armature rotates under the poles, so the torque also pulsates. This can give rise to extra wear on bearings and the engin

Compute the starting torque with the starting compen sator, A three-phase, ...

A three-phase, 2200-V, 60-Hz, delta-connected, squirrel-cage induction motor, when started at full rated voltage, takes a starting current of 693 A from the line and develops a sta

Engineering design, following on from the first tma in this module, produce...

following on from the first tma in this module, produce a design report for one design of the product based on one of the scenarios covered on the following pages.

8. A road 300 m long is required to be illuminated b, Ask questio8. A road ...

Ask questio8. A road 300 m long is required to be illuminated by providing 40W fluorescent lamps. The width of the road is 4m. Design a street lighting scheme for obtaining minimu

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