How does Printed Circuit Fundamentals produce?
In 1798, Eli whitney,secured a government contract to produce 10000 muskets for $130000. Many didn't believe he could do it because producing guns at that time required skilled gunsmiths. Also, because each gun was slightly different, parts were not interchangeable. What Whitney envisioned, and successfully implemented, was a system where precise machine tools would produce individual parts of exact sizes and shapes. Operated by relatively unskilled labor, these machines would produce parts that could be assembled into many identical rifles. Other industrialists-Henry Ford, Cyrus McCormack, and Isaac Singer(of sewing machine fame)-were quick to follow suit, and the result was the industrial Revolution.
The field of electronics has had several similar revolutions. If you looked into an old-fashioned radio receiver, the first things you had notice would probably be the tubes. But, after the tubes, you'd probably notice the mess of wires connecting all the components together. Someone had to physically connect those wires and solder them. Of course, that means mistakes happen- you can't expect people to build radios without making errors. The more complicated the project, the more mistakes you can expect.

In the 1950s, companies started using printed Circuit borads(PCBs) to reduce costs and errors. The idea is quite simple. You start with an insulating substrate(the board) made of phenolic(a material made from paper and resin), fiberglass, or ceramic. Then you arrange for copper to be placed on the board in a particular pattern. This copper, which is bound to the substrate, conducts the electricity just like wires. Holes are drilled to allow components to mount to the board.

Offhand, this doesn't sound much better than wires. The trick is that automated processes can create the copper patterns on the board easily. Just as whitney's machines turned out perfect rifle barrels, it is possible for modern manufactures to mass-produce perfect circuit boards. Of course, the trick is how to actually do this. Several possible methods are available. You can take a board that already has copper laminated to it and remove the copper you don't want. This is usually done with a photographic process and chemicals that attack copper. However, it can also be done with a computer operated milling machine that mechanically chips away the copper you don't want.

Other ways to build PCBs exist. For example, you can start with a blank substrate board and electroplate the copper on the board. Some PCBs are not made photographically, but are made with a silk screen.

No matter what the method, the key is that, armed with some negatives (or a milling machine program), you can produce dozens or hundreds or even tens of thousands of boards, all precisely the same. The cost of producing these boards is relatively inexpensive, and there can be other advantages as well. For example, with precisely placed components, it is possible to use machines to insert the components into the board. Another machine can solder the parts, practically eliminating human involvement in the production process.

When PCBs first became widespread, producing them was high technology indeed. First, artwork(the pattern that shows where the copper should be on the board)was done by hand. Because the tolerances were inportant designers typically used drawings that were four times larger than life size. Then a special camera would take a picture of the artwork and reduce it. The resulting film would then be used in a complex manufacturing process.
Several things have happened to make PCBs more accessible than ever to the small company or hobbyist . First , computer programes are available that enable you to design PCB layouts easily. As with anything you do on the computer, you can correct errors, experiment with different layouts, and make changes very easily. You can even have the computer do a great deal of the work for you.
The industry have standardized format for describing PCB layouts. When you are satisfied with your design, you can simply email your files to any number of companies that will build the board to your specifications and ship it back to you. If you are willing to pay enough, you can design a board on Monday and have it in your hands by wednesday.
However, it is also possible to build your own boards with a modest investment in tools and chemicals. You can create film with a common computer printer. You can also use a laser printer(or copier) to directly transfer the pattern to the PCB material. Then several inexpensive and relatively safe chemical processes can be used to finish the job.
Like the gun, what was once the province of the specialized labor is now accessible to anyone who wants to build electronic circuits. That's a good thing, too. Modern circuits are getting harder and harder to build by hand. Working with normal integrated circuits is hard enough. With the trend toward tiny surface-mounted parts, PCBs are almost a necessity, even for prototyping or one-off projects.