What does “PCB (Printed Circuit Board)” mean?
A printed circuit or electronic card (PCB in English) is composed of a plate or several very thin superimposed plates (epoxy resin layers, fiberglass) with paths traced in order to conduct an electric current through electronic components.
PCBs are part of our daily life. They are found in all kinds of devices belonging to various fields of application, personal, industrial, pharmaceutical, aeronautics, space, telecom or others.
From a simple audio amplifier, a luminous vu-meter on a DJ mixer, to our computers, our smartphones, MP3 players, our children’s game consoles and other electronic devices such as routers, switches, servers contained in a data center (Google Datacenter) to go on the internet, and even the text you are reading at the moment: all depend on PCB to work.
How are PCBs made?
Electrical components of PCBs (Figure 2) exist in all sizes. Some are visible, smaller ones such as Surface Mounted Components (CMS) and others that are built into packages that are made up of millions of transistors smaller than micromillimeters.
All these components are mounted on the PCB which can contain several thousand components with different technical characteristics. Among the components are resistors, capacitors, diodes, transistors and other components such as integrated circuits, memories, processors, etc…
PCBs can be rigid or flexible, they are made with an insulating material like plastic, the copper or gold-plated traces are, for their part, conductive and placed on the PCB. Gold and copper are good conductors of electricity.
The components are fixed through small holes (lozenge PCB or vias) or placed on the PCB with solder, the most used material of which is tin.
Gold plated is used to trace the path of the current (the routing) which will pass through the various electronic components. These paths have different sizes depending on the electric current that will pass through them. All these traces are electrically connected through different areas of the printed circuit (PCB).
The PCB will be, according to the needs of the one who is going to draw the printed circuit, personal or professional, of different sizes, different materials and well-selected characteristics.
What role do PCBs play in my project at ALSTOM site?
These PCBs are first studied in the lab according to the needs of our customers from different countries around the world.
In our teams, they are calculated, then draw on CAD software (Computer Aided Design).Then sent to a PCB manufacturer who will make a prototype PCB, which then returns to the lab.
My job on the ALSTOM site: I control, test, modify the PCBs according to safety standards and ALSTOM’s configuration requirements.
I validate the Hardware part of the PCB, which is still, at this stage, a prototype. The PCB will be prepared to receive the Software versions.
PCBs will be first assembled and tested inside ALSTOM and, after validation, on trams, metro and/or trains.
Eventually PCBs can be manufactured by thousands.
For your information, in Belgium, most of the trams, subways and trains you use every day are made by ALSTOM.