What is a Circuit Board?
Simply speaking, It is an important electronic component, support for electronic components, and a carrier for the electrical interconnection of electronic components.
Simplify Instructions
Almost every electronic device, ranging from electronic watches and calculators to computers, communication electronic equipment, and military weapon systems, as long as there are electronic components such as integrated circuits, in order to make the electrical interconnection between the various components, use printed circuit boards.
Circuit boards are made up of many components, which are inherently complex and sophisticated, with the layers of the board connected together by traces, some of which are dedicated to power and others to enhance the signal.
What does a circuit board do?
Without it, electronic equipment cannot function, as most advanced equipment requires.
Can help electronic devices perform basic tasks such as computing, communicating, and transferring data.
The main use is to send electronic signals to other components of an electronic device. This allows signals to flow freely, so every part of the device can communicate with every other part.
It also keeps all electronic components properly insulated to prevent overheating. As a result, the service life of the device and its components can be extended.
They are also customizable, which enables them to receive signals and perform calculations.
With the development of science and technology, circuit boards are updated every day.
Classification
Circuit boards are divided into three major categories: single-sided, double-sided, and multi-layer circuit boards according to the number of layers.
The first is single-sided, with parts concentrated on one side and wires on the other. Because the wires only appear on one side, this kind of PCB is called a single-sided circuit board.
Single panel is usually simple to make and low cost, but the disadvantage is that it cannot be applied to too complicated products.
Double-sided is an extension of single-sided. When single-layer wiring cannot meet the needs of electronic products, double-sided is used.
Both sides have copper cladding and traces, and the lines between the two layers can be conducted through vias to form the required network connections.
A multi-layer board refers to a printed board with more than three conductive pattern layers and insulating materials in between, and the conductive patterns are interconnected as required.
Multilayer circuit board is the product of the development of electronic information technology in the direction of high speed, multi-function, large capacity, small volume, thinning and light weight.
Circuit boards are divided into (FPC), (PCB), (FPCB) according to their characteristics.
Structure
It is mainly composed of pads, vias, mounting holes, wires, components, connectors, fillings, electrical boundaries, etc.
The main functions of each component are as follows:
Pad: A metal hole for soldering component pins.
Vias: There are metal vias and non-metal vias, where metal vias are used to connect component pins between layers.
Mounting holes: used to fix the circuit board.
Wire: An electrical network copper film used to connect component pins.
Connector: A component used for connection between circuit boards.
Filling: The copper used for the ground wire network can effectively reduce the impedance.
Electrical Boundary: Used to determine the size of the circuit board, and all components on the circuit board must not exceed this boundary.
Brief History of Circuit Boards
Who Made the First PCB?
The development of the methods used for modern printed circuit boards began in the early 20th century.
Charles Ducasse patented a method of electroplating circuit patterns in 1925.
Since then, the evolution of circuit boards has begun.
Evolution Timeline
The creator of the circuit board is the Austrian Paul Eisler (Paul Eisler).
In 1936, he first used printed circuit boards in radios.
In 1943, Americans mostly used the technology in military radios.
In 1948, the United States officially recognized the invention for commercial use.
Printed circuit boards have only been widely used since the 1960s.
Since the 1980s, boards have been smaller and cheaper to produce, but some additional difficulties have been encountered in repairing faulty boards.
Since the 1990s, the use of multi-layer panels has become more frequent. As a result, the size is further reduced and both flexible and rigid PCBs are being integrated into different devices.
In 1995, PCB manufacturers began using microvia technology to produce high-density interconnect (HDI) PCBs.
How much is a circuit board for?
The production cost of a circuit board typically ranges from 50 cents to around $500, depending on many different factors that may depend on the board; size, number of holes, number of layers and the final cost of manufacture.
The production cost and cost are relatively close, but as the number increases, the production cost shrinks rapidly.
Today’s Circuit Boards
Today, circuit boards have eliminated the chemical PCBs. The terms printed circuit board and printed wiring board (PWB) are now used interchangeably in the industry, although printed circuit board is now the more commonly used term.
Recent advances in 3D printing mean there are several new technologies in manufacturing. 3D printed electronics (PE) can be used to print objects layer by layer, which can then be printed using liquid inks that contain electronic functionality.
Since 1977, circuit boards have developed in the direction of high speed, multi-function, large capacity, small volume, thinning and light weight.
How the circuit board works
The working principle of the circuit board is to use the board-based insulating material to isolate the surface copper foil conductive layer, so that the current flows in various components along the pre-designed route to complete tasks such as work, amplification, attenuation, modulation, demodulation, and coding. and other functions.
In the most basic circuit boards, the parts are concentrated on one side and the wires are concentrated on the other side. Because the wires only appear on one side, this type of PCB is called single-sided.
Multi-layer boards, with multiple layers of wires, must have appropriate circuit connections between the two layers. The bridge between the circuits is called a via.
The basic design process of a circuit board can be divided into the following four steps:
(1) Design of circuit schematic diagram—The design of circuit schematic diagram mainly uses the schematic diagram to draw the schematic diagram.
(2) Generate a network report—a network report is a report showing the link relationship between the circuit principle and the various components in it. It is the bridge and link connecting the circuit schematic design and the circuit board design. Through the network report of the circuit schematic, The connection between the components can be found quickly, thus providing convenience for the subsequent PCB design.
(3) Design of printed circuit board—The design of printed circuit board is what we usually call PCB design. It is the final form converted from the circuit schematic diagram. The related design of this part is larger than the design of the circuit schematic diagram. difficulty.
(4) Generate printed circuit board report — After the printed circuit board design is completed, it is necessary to generate various reports, such as generating pin report, circuit board information report, network status report, etc., and finally print out the printed circuit diagram.
Why Is The PCB Green?
Epoxy Is Green
The epoxy that was originally used to make the PCB solder mask was green. Today, green is still the most common color. The low cost of production makes it still the default color used for PCBs today.
Easy to Check
Another practical reason to choose green is for a relaxing effect when inspecting circuit boards and looking for faults.
Green is also considered the best color for inspecting PCBs to avoid fatigue for those who spend a lot of time checking for problems. Inspectors usually use bright lights to inspect, so anything that reduces fatigue is helpful.
Green Is Cheaper
Cost is a major factor when manufacturing PCBs, and since green is the most popular and common color, it is also the cheapest. Of course, the PCB may not be green. Different colors can be used to distinguish different PCBs. Blue, black, red and white are available for standard production, or we can also produce and customize the desired color upon request.
Layers of the circuit board
Many types of working layers of circuit boards, such as signal layer, protective layer, silk screen layer, internal layer, etc.
The roles of the various levels are briefly described as follows:
⑴Signal layer: mainly used to place components or wiring. Protel DXP usually contains 30 middle layers, namely Mid Layer1~Mid Layer30, the middle layer is used to arrange signal lines, and the top and bottom layers are used to place components or copper.
(2) Protective layer: It is mainly used to ensure that the places on the circuit board that do not need tin plating are not tinned, so as to ensure the reliability of the operation of the circuit board. Among them, Top Paste and Bottom Paste are the top solder mask layer and bottom solder mask layer respectively; Top Solder and Bottom Solder are the solder paste protection layer and the bottom solder paste protection layer respectively.
(3) Silk screen layer: It is mainly used to print the serial number, production number, company name, etc. of the components on the circuit board.
⑷Internal layer: mainly used as a signal wiring layer, Protel DXP contains a total of 16 internal layers.
⑸ Other layers: mainly include 4 types of layers.
Drill Guide: Mainly used for drilling holes on printed circuit boards.
Keep-Out Layer: Mainly used to draw the electrical border of the circuit board.
Drill Drawing: Mainly used to set the drill shape.
Multi-Layer: Mainly used to set multi-faceted layers.
Why are circuit boards so expensive?
The difference in the materials used leads to price differences in prices.
Board thickness from 0.2mm to 3.0mm, copper thickness from 0.5oz to 3oz.
The price difference of different solder mask inks.
There is also a certain price difference between ordinary thermosetting oil and photosensitive green oil.
The price difference of different surface treatment processes.
OSP, lead spray tin, lead-free spray tin, gold plating, immersion gold, and some combination processes, etc., the prices of the above processes are getting higher and higher.
Difficulty price difference.
If two circuit boards are the same, but the line width and line spacing are different, the production cost will also be different.
Secondly, there are some designs that do not follow the common process and will be more expensive, such as half-hole, buried blind hole, hole-in-disk, and carbon oil on the key board.
The price difference of copper foil thickness is different.
Common copper and platinum thicknesses are: 18um (1/2OZ), 35um (1OZ), 70um (2OZ), 105um (3OZ), 140um (4OZ), etc. The price of copper foil thickness is getting higher and higher.
Different price differences for quality acceptance criteria.
IPC2, IPC3, enterprise standard, military standard, the higher the standard, the higher the price will be.
The price difference between the mold fee and the test fee.
Mold fee, if there is no additional cost for samples and small batches, molds need to be opened for large batches, so there is a set of mold costs.
Test fee, the prototype generally adopts flying probe test, which will incur costs.
Price difference caused by different payment methods
The shorter the payment time, the lower the price.
Price difference between order quantity and delivery time.
The smaller the quantity, the more expensive the price. Even 1PCS requires materials and the same process.
The information provided by the delivery date should be complete. The sooner the information is completed, the earlier the delivery date will be.
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