A PCB
All about PCB assemblies
Many modern products require the use of complicated circuits, so complicated that indeed it would be impractical to have them all individually wired, soldered and tested by hand. The solution to the problem is the Printed Circuit Board, commonly referred to as a PCB, which can make an extremely large and complicated circuit operate in an incredibly small and compact area. Ever seen the inside of a mobile phone or laptop that has been dissected? Remember that green sheet of plastic with all the sparkling wires and hundreds of tiny electrical components attached to it? That's a PCB Assembly.
The principle behind a PCB is incredibly simple. The green plastic is an electrical insulator, but on the plastic run many tiny little channels of electrical conductor. These channels connect the systematically placed components on the board. And there we have it! No wires, no fault-prone terminals, just a circuit enclosed in a reliable and hardy plastic case.
The word "printed", however, refers to the little channels of electrical conductor on the plastic. Of course, every different product requires a different circuit for its operation, so it is of a high industrial importance that PCBs can be manufactured entirely to the specifications of the producer. This is achieved by means of a highly automated factory procedure involving computer design and robotic assembly machines. The method is in fact so important to modern industry that it has been nearly perfected worldwide.
Although the largest and most prolific PCB assembly plants are in the Far East in countries such as China, Thailand and Japan, there are many smaller, higher quality producers thriving in European and American countries such as the USA, Germany, France, Spain and the UK. British manufacturers may actually choose to have their PCBs assembled in the UK as quality can be more closely controlled, contact with manufacturers is easier (from both distance and linguistic points) and less money is needed for importing/exporting. Many PCB assembly factories here in the UK or Europe have as large a capability as those in the Far East, and are often as quick and cheap, but with a reputation for consistently higher quality.
A PCB assembly method often used in modern industrial technology is SMT, or surface mount technology. This technique does away with the need to first drill holes in the PCBs before adding components: instead they are literally mounted, with solder, on the surface of the board. Although there are many advantages over the more tradition through-hole technology, such as greater stability, and higher production speed, there are also downsides, such as high initial cost and difficulty to repair (unless a very steady hand, expertise and the right tools are available).
