Printed circuits

In electronics, a printed circuit board or PCB (Printed Circuit Board) is a surface made up of paths, points, tracks or buses of conductive material laminated on a non-conductive base.

The printed circuit is used to electrically connect through the conductive tracks, and mechanically support, by means of the base, a set of electronic components. The tracks are generally made of copper or tinned copper, while the base is generally made of fiberglass resins, phenolic resins, aluminum, ceramics, etc.

In low-cost and / or high-consumption productions, materials such as FR2 or FR3 are used, while for professional circuits, fiberglass is usually used, better known commercially as FR4 (flame retardant 4).

Phenolic resin and hard paper are the material that produces FR2. Hard phenolic paper is an inexpensive material that was previously used in the high-volume production of printed circuit boards. But phenolic resin is no longer used due to its qualitative deficiencies. Phenolic resin is known to emit small amounts of formaldehyde and phenol. This represents a considerable health risk. On the other hand, epoxy resin and hard paper are the materials that make FR3. Epoxy resin and hard paper are inexpensive materials that are ideal for PCB manufacturers operating on a limited budget.

Fiberglass or FR4 is a hard material and requires carbide tooling for production machining of tungsten, since the glass fibers with which these plates are composed is an abrasive product and the usual bits used for metal last very little.

In circuits for high frequencies, if the application requires it, ceramic materials such as Rogers or PTFE (for example Teflon from Dupont) are used.

There are also flexible circuits made of celluloid or some similar material and these are frequently used in keyboards, in communication buses between plates, etc. When it is necessary to dissipate a lot of heat in a printed circuit, for example copper or aluminum is used as a substrate and to which a flexible circuit is glued on one side, since a heat sink is housed on the other. This type is often used for example in led lighting.

Generally, in our section you will only find printed circuits made of FR4 or fiberglass material. The most commercial has a thickness of 1.6 mm and which has one or two copper layers of 35 µm copper attached. Giving origin to plates that we call 1-sided or 2-sided. We call this type of plates virgin and they come in different sizes.

In order to make a printed circuit or PCB we can use different techniques. The two most common at the amateur level are: painting with an indelible marker the circuit on one of these virgin plates and later attacking the excess copper with a chemical compound that eliminates the unpainted part or using a photosensitized plate, which is no more that a virgin plate to which a photosensitive emulsion has adhered and through a photographic process we paint our drawing on the emulsion, later we reveal it and then we attack it like virgin plates.

If we want to make a prototype, there are other types of plates already drilled that have nodes or copper islands and / or tracks.

By joining the different components with cables or soldering, we can make our electronic circuit with this wiring and soldering technique, but we can also use these boards using the wire-wrap technique that avoids having to use the soldering iron to component wiring.

In this section you will find blank boards, photosensitized boards, chemical elements and other related products for the elaboration of your PCB, as well as prototyping boards, printed circuit spacers and guides, such as printed circuit adapters for integrated circuits

CN15