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What is a PCB

2020-06-23

What is a printed circuit board, or What is a PCB?

You may be trying to find the best answer to the question “What is a pcb?” A 인쇄 회로 기판 , or PCB, is made of an electrically insulating material (like getinax, textolite, fibreglass, or other similar dielectrics). That has thin conductive plates (called “printed conductors”) on its surface. It has pads that can be used to connect and install radio parts like modules and integrated circuits. These are electronic components used widely now a days.

So that’s another answer to the question, “What is a PCB?” A printed circuit board is a piece of equipment that has fixed electrical connections on a base that doesn’t conduct electricity. There are also multi layered pcbs that are used in special purposes.

The main parts of a printed circuit board are the dielectric base (which can be rigid or flexible) and the conductors, which are placed on the surface of the base. A printed circuit board has a dielectric base and conductors. These are the only two parts that make it a printed circuit board.

To put the parts in place and connect them to the wires. There are also other parts like contact pads, metallized transitions and mounting holes, connector lamellas, sections for removing heat, shielding and current-carrying surfaces, etc.

When electronic equipment design made the switch to printed circuit boards, it was like a giant step forward. A printed circuit board serves both as a place to put radio parts and as a way to connect those electrical equipment. If there isn’t enough insulation resistance between the conductors and other conductive parts of the printed circuit board, or PCB Board, then the second function can’t happen. Because of this, the printed circuit board’s base must be an insulator.

PCB

The history of printed circuit boards is told in the following way:

To learn more about what is a pcb? Let’s begin. At the start of the 20th century, a German engineer named Albert Parker Hanson worked on making phones work. He made something that is thought to be the first type of printed circuit board ever made.

People think that printed circuit boards “came into being” in the year 1902. When the inventor put in a request for a patent with the office in his home country.

Hansen’s circuit board was made from bronze (or copper) foil that was stamped or cut out. The conductive layer that was made was then stuck to a dielectric, which was paraffin-soaked paper. Even so, Hansen pasted the foil on both sides to make sure there were more conductors. This made a double-sided printed circuit board.

The person who made the printed circuit board also used holes to connect things. Hansen’s works explain how conductors are made using electroplating or conductive inks, which are made of metal powder mixed with an adhesive.

PCB manufacturing

History Explained: What is a PCB?

At first, only “additive” technologies were used to make printed circuit boards. This means that the pattern was put on the dielectric by glueing or spraying material.

Thomas Edison had some of the same ideas. Edison wrote a letter to Frank Sprague, who later started Sprague Electric, in which he explained three ways to draw a conductor.

1. The pattern is made by sticking graphite or bronze to a surface that is free of dust and then crushing them into dust.

2. The pattern is made on the dielectric itself. Lapis (silver nitrate) is used to make the image, and then salt is used to get the silver back.

The conductor is a piece of gold foil with a design on it.

Scientists Explained, what is a PCB?

Even though Edison didn’t use the term “printed circuit boards,” almost all of the ideas above are still used in technology today. Today’s thin-film technologies are based on the first of these. By removing metals from salt, the second method is often used to coat things. Many more scientists defined, What is a PCB board. like:

Arthur Berry got a patent for his way of making printed circuit boards by taking away parts. The developer suggested covering the metal base with a layer of resistive material and etching away parts of the surface that are not protected. Ellis Bassit from the United States came up with and got a patent for a way to use photosensitive materials to make printed circuit boards in 1922.

Charles Duclas, an American, came up with the idea of metallization of conductors. The basic idea was to fill channels with a soft dielectric (for example, wax). Which were then filled with conductive pastes made of metal by an electrochemical process.

More details about What is a PCB?:

Many patents were given out in the 1920s and 1930s for the design of printed circuit boards and the ways to make them. Most of the first methods used to make printed circuit boards were still additive (the development of the ideas of Thomas Edison). But the printed circuit board as we know it today came about because printing technology was used to make it.

The English word “printing plate,” which means “printed form” or “matrix,” is the exact same thing as “printed circuit board.” So, the real “father of printed circuit boards” is thought to be the Austrian engineer Paul Eisler.

He was the first person to figure out that printing (subtractive) technologies can be used to make printed circuit boards in large quantities. In subtractive technologies, an image is made by taking away bits that aren’t needed. Paul Eisler figured out how to galvanically deposit copper foil and use chlorine iron to etch it.

How Is PCB Assembly Done?

So, when we ask, “What is a PCB board?” it’s important to know what it’s made of. Table 1 lists the main types and sizes of materials that are used to make MPP, as well as their main properties. Most printed circuit boards are made with standard fibreglass laminate type FR4, which can be used at temperatures from –50 to +110°C and has a glass transition temperature (Tg) of about 135°C.

Depending on the supplier and the type of material, Dk can be anywhere from 3.8 to 4.5. High-temperature FR4 High Tg or FR5 is used when heat resistance needs to be increased or when mounting PCB boards in an oven using lead-free technology (up to 260 °C).

Polyimide is used when there is a need for continuous work at high temperatures or sudden changes in temperature. Polyimide is also used to make more reliable circuit boards, both for the military and in other situations where electrical strength needs to be increased.

The cost of these materials is more than the cost of FR4, and the cost of FR4 is shown in the last column of table 1 as a comparison. Fig. 4, 5, and 6 show examples of boards with different types of dielectric. Everyone who uses single-layer or multi-layer printed circuit boards needs to know about the parameters of the materials they are made of.

This is especially true for high-speed and microwave devices that use single-layer printed circuit boards. Developers have to do things like: calculate the wave impedance of the conductors on the board; calculate the high-voltage insulation between the layers; and choose the structure of blind and hidden holes.

Tables 2–6 show what options are available and how thick different materials are. Keep in mind that the thickness of the material can be off by up to 10 percent, so the thickness of the finished multilayer board can’t be off by less than 10 percent.

Materials for printed circuit boards and how they are used?

Typical PCB designs for the best Printed Circuit Board are based on using standard FR4 fibreglass, which has an operating temperature range of –50 to +110 ° C and a glass transition temperature Tg (softening) of about 135 ° C.

What is a PCB in high-temperature? FR4 High Tg or FR5 is used when heat resistance needs to be better or when mounting boards in an oven using lead-free technology (up to 260 °C).

Polyimide is used when there is a need for continuous work at high temperatures or sudden changes in temperature. Polyimide is also used to make more reliable circuit boards, both for the military and in other situations where electrical strength needs to be increased.

Dielectric constant

What is a PCB, how does a PCB work, and why is it? Think about the coatings on the copper pads that are used to solder elements. Most of the time, a tin-lead alloy, or PIC, is used to cover the sites. The process of putting solder on a surface and making it even is called HAL or HASL.

These terms come from the English phrase “Hot Air Solder Leveling,” which means “levelling the solder with hot air.” This coating makes it easy for the pads to be soldered.

But it is being replaced by coatings that are more modern and usually meet the needs of the international RoHS directive.

This directive says that products can’t have any harmful substances, like lead, in them. RoHS does not yet apply to our country, but it is not a waste of time to remember that it exists.

Table 7 shows the different ways that MPP sites could be covered.

HASL is usually used unless something else is said.

Immersion (chemical) gilding is used to make the surface of the board more even, which is especially important for BGA pads. However, it makes the board a little harder to solder. Soldering in the furnace is done in a way that is similar to HASL, but soldering by hand requires the use of special fluxes. Copper won’t oxidise on its surface if it has an organic coating, or OSP.

Solderability’s weakness is that it doesn’t last long (less than 6 months).

Immersion tin has a flat surface and works well for soldering, but it has a short shelf life. The properties of lead-free HAL are the same as those of lead-containing HAL, but the solder is made up of about 99.8 percent tin and 0.2 percent other materials.

When the board is in use, the contacts of the knife connectors that move against each other are coated with a thicker and more rigid layer of golden finger. For both kinds of gilding, a nickel layer is used to stop gold from spreading.

Insulating coatings are used to cover the sides of conductors that aren’t meant to be soldered.

What is a PCB in marking?

Paint is put on the board over the mask to make it easier to figure out what the board is and what parts are on it.

Peel-off mask: This is put on parts of the board that need to be protected temporarily, like from soldering. In the future, it will be easy to take off because it is made of a rubber-like material that just peels off.

Carbon contact coating is put on parts of the board where keyboards make contact. The coating is good at conducting electricity, doesn’t rust, and doesn’t wear away easily.

Resistive elements made of graphite can be put on the surface of the board to act as resistors. Unfortunately, the values are not very accurate. They are not more accurate than 20% (with laser adjustment, they can be up to 5%).

Silver contact jumpers can be used as extra conductors to add another layer of conductivity where there isn’t enough room for tracing. They are mostly used to make printed circuit boards with one layer or two.

What are PCBs? What is PCB Fabricator?

A simple wire, which is usually wrapped in insulation, is the most basic thing that came before printed circuit boards. He was flawed in a big way. When there were a lot of vibrations, he asked that it be fixed inside the CEA with more mechanical parts.

To do this, we used carriers on which the radio elements were installed, the radio elements themselves, and structural elements for making connections between the radio elements and fixing the wires. This is an installation with space.

Printed circuit boards don’t have any of these flaws. Their conductors are fixed to the surface, and their positions are fixed, so they can figure out how they connect to each other. In general, printed circuit boards now have designs that are getting closer to being flat.

What is a printed circuit board with only one side? or What is a PCB with only one side? It is a flat piece of metal with printed wires on one side. In double-sided printed circuit boards, the empty back side of the plate was also used by the conductors.

In Fig. 1, you can see small pieces of the simplest single-sided and double-sided printed circuit boards.

What is a PCB board with two sides?

Types of PCB are explained along with the manufacturing process.

The first step from the plane to the volume was to use them instead of single-sided paper. If we don’t think about the substrate of a double-sided printed circuit board, we get a three-dimensional structure of conductors. This step was done quickly, by the way. In his application, Albert Hanson already mentioned that it might be possible to put conductors on both sides of the substrate and connect them using holes.

Microelectronics, the latest advancement in electronics, has led to the use of components with more than one pin (a chip can have more than 200 pins), and the number of electronic parts has grown. In turn, the use of digital microcircuits and the increase in their speed have made it more important to shield them and make sure that power gets to all of their parts. Why did multilayer boards of digital devices have special shielding conductive layers? (for example, computers).

All of this led to more connections and more complicated connections, which led to a rise in the number of layers. It can be a lot more than ten on modern printed circuit boards. The multilayer printed circuit board has, in a way, gotten bigger.

How to design printed circuit boards with more than one layer?

Think about how a typical multilayer board is made. In the first, most common type, the inside layers of the board are made of copper-laminated fibreglass that is laminated on both sides. This is called the “core.” The outside layers are made of copper foil that is pressed together with the inside layers using a glue called “prepreg.”

A multilayer printed circuit board is made in the shape of a “pie” by pressing it at a high temperature. Holes are then drilled and metallized in the pie. When the outer layers are made from “cores” held together by a prepreg, the second option is less common.

This is a simplified explanation. Based on these choices, there are many other ways to make the design. But the main idea is that prepreg is used to hold the layers together. Two bilateral “cores” can’t be next to each other without a prepreg gasket, but a foil-prepreg-foil-prepreg-foil-prepreg-foil-prepreg-foil-prepreg-foil-prepreg-foil-prepreg-foil-pre It is used a lot on boards that have a lot of blind and hidden holes.

In terms of price, two-thirds of all printed circuit boards made in the world are now multilayer boards. Even though they are less useful in terms of size than single- and double-sided boards.

Fig. 2 shows a simplified schematic of a small part of the design of a modern multilayer printed circuit board. Conductors are not only on the surface of these printed circuit boards, but also inside the substrate. At the same time, the conductors’ layers were kept in the same place in relation to each other (a consequence of the use of planar printing technologies).

One-sided, double-sided, and multilayer PCB boards.

The names of printed circuit boards and their parts always have something to do with layering, like “one-sided,” “double-sided,” “multi-layer,” etc.

Interlayer transitions (vias) and micro-transitions (microvias) are used to switch between the layers of MPP. Fig. 3.a. Interlayer transitions can be done as through holes that connect the outer layers to each other and to the inner layers.

pcb

There are also blind and hidden changes for Rigid PCBs

A blind transition is a metal-lined channel that connects two parts of a board. It can only be seen from the top or bottom of the board.

The inner layers of the board are connected by hidden transitions. By using them, you can make wiring boards a lot easier. For example, a 12-layer MPP design can be made to work like an 8-ply commutation.

Microjunctions that connect contact platforms and signal layers are made especially for surface mounting.

For making multilayer printed circuit boards, gluing pads called “prepregs” are used to stick together several sheets of dielectric foil that have been laminated together.

Regarding Figure 3. White shows the prepreg. When a multilayer printed circuit board is heated and pressed, Prepreg glues the layers together.

When the number of signal layers on a printed circuit board or a multilayer printed circuit board goes up, the total thickness of the board grows too quickly.

In this case, it’s important to think about how thick the board is compared to how big the holes are, which is a very hard parameter for the through-hole metallization process.

But, even though the metallization of small-diameter through holes is hard, manufacturers of multilayer PCBs prefer to make boards with a high installation density by using a large number of cheap layers instead of a small number of high-density, but more expensive, layers.

Figure 3.c shows an example of how the layers of a multilayer printed circuit board are laid out and how thick they are.

This article told us what a PCB is. How PCB works? and How to make a PCB board.

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