Spread time - power semiconductor devices , Electrical Engineering

Assignment Help:

Spread Time (ts)

During  spread time anode  voltage  falls from 10% Ia  to the  on state  voltage  drop  and anode  current  rises  from 90% Ia  to final  value  of anode  current i ,e Ia in this period whole  charges injected from   gate spreads over the entire section of  cathode and anode  current  reaches at steady state  condition.

There the total turn on time  ( ton ) can be written  as

Ton = td + Ir + ts

In these  intervals td tr and ts the rise time is high  a s compared to other. If  rise time it  is reduced beyond  a limit thyrisotr may get destroyed because rate of  rise  of anode  current  may be  large  as compared to the spread velocity of charges and this  may forms a  local  hot spot on the cathode surface of SCR. Turn on  time depends on gate  current. It can be  reduced by using  higher  value of gate  currents.

 


Related Discussions:- Spread time - power semiconductor devices

Cycloconverter scherbius drive - motor control , Cycloconverter  Scherbius...

Cycloconverter  Scherbius Drive In this  drive  instead of dual controlled used in link  scherbius  drive one  phase  controlled  line commutated cyclconverter is used. This

Combination of uni-selectors and two motion selectors, Q Using a combinatio...

Q Using a combination of Uni-selectors and two motion selectors, draw a diagram of thousand line exchange and illustrate its working. Ans: The diagram for such an exchange i

Find the resistance of wire, The resistance of a wire is 60 ? at 25 o C and...

The resistance of a wire is 60 ? at 25 o C and 65? at 75 o C. Find the resistance of wire at 0 o C and value of temperature co-efficient at 0 o C. Ans: Given R 25 = 60 ? a

Calculate the speed of motor when armature current is 25 a, Q. The magnetiz...

Q. The magnetization curve taken at 1000 r/min on a 200-V dc series motor has the following data: Field current, A: 5 10 15 20 25 30 Voltage, A: 80 160 202 222 236 244 Th

What are the features used mode 1 in 8255, What are the features used mode ...

What are the features used mode 1 in 8255? Two groups - group A and group B are available for stored data transfer. 1. Each group have one 8-bit data I/O port and one 4-bit

Equivalent circuit of unijunction transistor, Equivalent Circuit : Th...

Equivalent Circuit : The equivalent circuit of a UJT is shown in fig. The P - N junction represented in the emitter by a diode. Silicon bar being lightly doped has a high res

Relative and absolute motion measuring device, a) With the help of a neat a...

a) With the help of a neat and clean sketch illustrate the difference between relative and absolute motion measuring device. b) Discuss electromechanical methods for calculating

Determine maximum neutral current-power factor, 1.)  A three phase, D0 HP, ...

1.)  A three phase, D0 HP, 1765 rpm, BA0 V induction motor operating at three quarter load has an efficiency of 91% and a power factor of 87%. Determine active power, apparent pow

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