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).
Explain ionic polarisation. Ionic Polarisation: It takes account of the fact that while some of the atoms in a molecule contain an excess positive or negative charge that of
winding turns of 415v step down transformer on 50%, 60% & 80% tapping
Q. What are the performance measures of oscillator circuits? 1. Stability: This is determined by the passive components. R, C and L determine frequency of oscillations. If R ch
Q. Motoring mode of rotating machines? The motoring mode has electric power input and mechanical power output. The electromagnetic torque Te drives the machine against the load
In this Project you will simulate a Security Alarm system using the Quick flash board. A switch is placed as shown in the figure below. The main goal of this project is: Task 1:
Disadvantages of SDR 1. Power consumption is more due to rapid switching of modes 2. Hardware design is not easy 3. Software bugs exist in the system
A linear circuit component is one that has a linear I V characteristic
Low and high resistivity materials and their applications
Q. A Silicon Transistor Whose Common Emitter Output Characteristics Are Shown In Dig Is Used In The Circuit With V cc =22.5v, R c =5.6k, R e =1k, R 2 =10k, And R 1 =90
For the amplifier circuit shown below estimate the mid band voltage gain if the EARLY voltage (V A ) of the current mirror transistors is 80 volts. Assume the d.c biasing is optim
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