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!
Surface Mount Devices (SMDs) are new components designed with soldering pads or short leads. They are much smaller in size as compared to leaded components. The SMDs are directly attached or inserted on the surface of the PCB and then soldered. In the conventional PCB assembly method, the components have leads for insertions into the holes made for the purpose into the boards and are soldered on opposite side of the board. But in surface mount device the components or devices are called surface mount components have leads small then the conventional components which can be soldered on the foot print of the broad directly. In other words in surface mount technology, holes are not drilled and components (specially manufactured) are soldered on the copper side of the board. Chip capacitors, chip resistors, chip inductors are the examples of passive SMDs, while SO-8, So-28, SOT-23 chip carriers are examples of active SMDs. The chip capacitors are multi layer ceramic in value from 1Pf to 1μf or tantalum type with value from 0.22μf to 10μf. The chip resistors are either thick film or thin film type and are available with 1% accuracy. Chip inductors of few mH are available.
ADVANTAGES OF SMDs:
Reduced size and weight. Lower cost. Save lead pre-forming. Components can be maintained from both sides of PCB. Automated high yield production. One machine places most of the components. Smaller production and small area. Smaller size, leadless, low cost. Improved high frequency performance. High dimensions standards. Short interconnections. Better performance. Improved area efficiency. Easy to use computer aided design and manufacture method.
DISADVANTAGES OF SMDs:
Repairs difficult. Generally ultra low power products. Completely new production method and investment. Very high starting costs. New technology, new reliability profile, new problems. Investment in quantity and reliability testing. Difficult to assemble odd shaped components. Must use tape mounted components. Totally new specifications. Needs new manufacturing facilities. Limited power handling. Bread boarding is difficult due to greater power density. PCB heats up. Need new interconnection systems. Unavoidable temperature gradients.
What do you understand by half period zones? What is their other name? Distinguish between physical and geometric (wave) approximations of light.
define biased clipper?
Q. How can we increase the current sensitivity of a galvanometer? The current sensitivity of a galvanometer is able to be increased by (i) Rising the number of turns (ii
Applications of Superconductors - 1. Electrical Machines 2. Power Cables 3. Electro Magnets 4. Amplifiers 5. Cryotron 6. Magnetic Leviation 7. A 15 Phases
Physical interpretation of wave function : Einstein proposed a historic relationship between energy and mass using postulates of STR. The variation of mass with velocity has modif
A 250 N crate is sitting on a 30 degree inclined plane. The frictional force is larger than the component of the crate's weight parallel to the inclined plane, so that the crate do
Q. Why does the sky appear blue in colour? As-per to the Rayleigh's scattering law the shorter wavelengths are scattered much more than the longer wavelengths. The blue look o
.Define like and unlike parallel forces
Explain Scalars and Vectors This is one of the harder ideas to get used to when you start learning physics. The trick is to see that there is one basic difference between a sca
Show that the spectrum of thermal radiation for T ¼ 300K peaks at approximately 10 microns.
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