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!
In single sided PCB the conductor tracks run only on one side of copper clad board. Thus crossing of conductors is not permitted. Base material is chosen as per the application. It is mechanically and chemically cleaned. Then the photo resist solution is evenly applied. Photo resist is a organic solution, which when exposed to light of proper wavelengths, change their solubility in the developers. There are two types of photo resist (1) Negative acting photo resist. (2) Positive acting photo resist. Negative acting photo resist is a mixture of which is initially soluble in its developer but after exposure to light, it is not soluble. So the unexposed soluble is selectively dissolved and washed away, leaving the desired resist pattern on the copper clad laminate. Coating of photo resist is done by
(1) Spray coating
(2) Dip coating
(3) Roller coating
The coated copper-clad laminate and film negative are kept in glass frame in intimate contact with each other. The assembly is exposed to ultra violet light for 3 minutes. The exposed board is rinsed in the developer tank. Proper developer has to be taken and used for a particular photo resist. Then the PCB is coloured in a tray. The dye revels the faults due to contrast. The faults are then separated by retouching. Etching eliminates the unwanted copper. Spray etching gives best results. Ferric chloride or cupric chloride is used as etching materials. Cupric chloride is regenerative and is thus preferred to ferric chloride. The etching solution is kept agitating by circulating low pressure air nozzles. Than the board is washed with water and dried. The board is then drilled with high speed drilling machine. The drill sizes range from 0.5mm to 1.8mm. Centring of hole on the land pad is done automatically.
Neutron is a fundamental particle carrying: (1)A charge of +1 unit and a mass of 1 unit (2)No charge and a mass of 1 unit (3)No charge and no mass (4) A charg of -1
What are wave fronts? (Physics) A wave front is an imaginary surface joining all points in space that are reached at the similar instant by a wave propagating by a medium. L
Is a sewing needle magnetic or non magnetic? Answer:- When you purchase it in the store it isn't magnetized but if you rub it with a magnet it becomes magnetic.
What is a capacitor ? A capacitor is basically a two conductors conencted with an insulator.... It stores great amount of charge!
calour formed in pure and impure spectrum
Capacity
what is gravitional constant? mention its SI value
Q. What do you mean by Ant reflecting Films? When a beam of light travels normally from a medium of refractive index µ 2 to a medium of refractive index µ 1 , a part of light
(1) The current in a super conductor once set up continuous for a very long time without attenuations. (2) The permeability of a super conducto
Physics assignment electron microscopy component, solve problem. can u solve these two problems with detailing and referencing if it needed
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