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).
(a) Describe why ordinary junction transistor is known as bipolar. (b) Describe working of NPN transistor as common Base configuration. Describe working of NPN transistor in
outline what three features you would add (choose the three that you feel would be most advantageous) to the 16 bit version of the processor in order to enhance its power.
Q. An antenna has beam widths of 3° and 10° in orthogonal planes and has a radiation ef?ciency factor of 0.6. Find the maximum radiation inten- sity if 1 kW is applied to the anten
A case study is required for development of different digital versions of band-pass filter corresponding to its analogue prototype described by the following normalised transfer fu
For a 50kW three phase rectifier connected at 415 V to a point of common coupling with a short circuit capacity 500kVA modelled as an inductive source, design filters to make the s
register array?
Question: Figure shows the basic circuit of the BJT Common Emitter Amplifier. (a) What is the function of RB, RC, Ci, Co and CE ? (b) (i) Sketch the d.c. equivalent circu
3-Phase 4 Wire Meters with CT and MD If load is commonly more than 50 A, CT operated meters should be used. It is to be remembered that CTs should be properly selected for acc
find the net value of power if an average value of energy is assumed to be $0.05/KWh, the capacity value is $30/kw-yr ...
how i make this and how cost of overall
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd