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.
When reverse bias is enhanced the electric field at the junction also enhances. At some stage the electric field becomes so high that it breaks the covalent bonds building electron
Q. Prove that for thin films, the interference pattern in reflected and transmitted light are complementary to each other. Also explain why the excessively thin films seen i
What do some fiber change the color of light? Actually, all fibers change the color of the light in one technique or other. Because of the physical characteristics of the condu
FORCE ON THE PARTICLE: For a mass m to have acceleration, a force given by F = ma is always required. In uniform circular motion, acceleration is of value v2/t and is directed tend
two blocks of mass 2kg and 4 kg are held together by a string force of 10N is applied on 2kg and 20N on 4kg find the tension in the string connected between two blocks
A simple calorimeter Small soup tins can be found which fit loosely into a 1lb. jam jar. If the top of the tin is cut off cleanly with a rotary type opener it serves as an good
The phenomenon of diffraction was first discovered by Girmaldi. Its experimental study was completed by Newton's and young. The theoretical explanation was first provided by Fresne
A force of 2.5kN is needed to lift a load. How much work is done if the load is lifted by 500cm? An electromagnet exerts a force of 12N and moves a soft iron armature by a dist
Q. An object of size 3.0 cm is placed 14cm in front of a concave lens of focal length 21 cm. Describe the image produced by the lens. What happens if the object is moved further aw
The electric field E because of a point charge at any point near it is explained as where q is the test charge and F is the force acting on it. What is the physical significance of
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