Spread time - power semiconductor devices , Electrical Engineering

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.


Posted Date: 4/2/2013 3:44:00 AM | Location : United States

Related Discussions:- Spread time - power semiconductor devices , Assignment Help, Ask Question on Spread time - power semiconductor devices , Get Answer, Expert's Help, Spread time - power semiconductor devices Discussions

Write discussion on Spread time - power semiconductor devices
Your posts are moderated
Related Questions

Discuss different kinds of Automation and their Advantages? Illustrate the Detroit type of Automation? Discuss basic Principles and strategies automation? Discuss the industries

The spectrum analyser plots amplitude against frequency, in other words it shows signals in the frequency domain. The spectrum analyser has the same trigger options as the oscillos

(a) Draw and illustrate the V-I characteristics of PN junction diode. How the characteristics reflected with change in temperature? (b) Describe physically why a PN junction dio

Q. Determine the time delay of the cable? An RG-213/U (radio guide 213/universal coaxial cable) is a small-sized, flexible, double-braided cable with silvered-copper conductors

What is the use of modem control unit in 8251? The modem control unit handles the modem handshake signals to coordinate the communication among the modem and the USART.

Q. emf produced by windings? The time variation of emf for a single conductor corresponds to the spatial variation of air-gap flux density. By suitable winding design, the harm

Q. Show Operation on JFET? The junction in the JFETis reverse-biased for normal operation.No gate current flows because of the reverse bias and all carriers flow from source to

What are tightly coupled systems or closely coupled systems? In a tightly coupled systems the microprocessor (either coprocessor or independent processors) might be share a com

Power Control A chopper converts  fixed  de input voltage to a controllable dc output voltage. It is  the single  stage dc to dc conversion device. It is a high  speed  on/ of