Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Reverse Recovery Characteristics
At the end of forward conduction in diode reverse current flows for a short time. The device doesn't attain its full blocking capability until the reverse current cease. The reverse current flows in the interval called reverse recovery time. During this time charge carriers stored in the diode at the end of forward conduction are removed. Actually when a power diode has been conduction in the forward direction sufficiently long to establish the steady state there will be a charge due to minority carriers present. Before the device can block in the reverse direction this charge must be extracted.
This extraction takes the from of a transient reverse current and this together with the reverse bias voltage results in additional power dissipation which reduces the rectification efficiency. Reverse recovery time is measured instant the current recovers to 25% of its peak reverse value. low reverse state forward current and low reverse bias voltage increase recovery time. High rate of all of anode current reduces recovery time but increase stored charge. High junction temperature is increase both recovery time and stored charge.
There are two parts of reverse recovery time. One is the time between zero crossing of forward current and peak reverse current. During this time period, charges stored in depletion region is removed. The other part of t measured form the instant of peak reverse current to the instant where 25% of peak reverse current is reached. During this time period charges from the two semiconductor layer are removed.
The shaded area in figure represents the stored charge or reverse recovery charge which must be removed during the reverse recovery time. The ration ½ is known as softness factor. Voltages transient occurs during the time diode recovers is measured by the factor.
b. forward voltage drop vf and forward current if gives the power loss in a diode. The total power loss in given by average value of V f i f during time t2 major power loss occurs in a diode. As shown in figure peak reverse current IFP is given by
I = RP = t1 di/ dt
Where Do/ dt is the rate of rise of reverse current. If the reverse recovery characteristics is assumed as a triangle shape then storage charge Q can be written as .
Q = ( ½) (IRP ) (t rr).
Unit to measure the electric charge Q?? The unit used to measure the quantity of electrical charge Q is called the coulomb C
Explain virtual memory. The term virtual memory considers as to something that appears to be present but in fact it is not. The virtual memory technique permits users to use m
On running the simulation, a data display will automatically open, similar to that shown in figure. The red circle is the source mismatch stability curve. This will give an indicat
Explain Hand shakingfor the allocation of addresses to memories and input output devices. Hand shaking: During an ASYNCHRONOUS data transfer is not based upon predetermined tim
Diffusion Current : The carrier currents are also due to concentration gradients in the doped material which lead to diffusion of carriers from high concentration region to l
SUB Instruction Op code format is of SUB instruction is Replace the three bit code of the register R from to obtain the op code of the required SUB instruction . o
Meter Field Testing and Installation Practices Here, we discuss the installation, commissioning and field testing of meters. Energy Meters - Installation and Commissionin
Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri
define all the symbols with their unit
Let the message signal m(t) = α cos (2πf m t) be used to either frequency-modulate or phase- modulate the carrier Ac cos(2πf c t). Find the modulated signal in each case.
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd