PCB - Printed Circuit Board
PCBs are the mechanical foundation on which electronic components can be mounted to complete the intended circuit.The PCB itself contains the conductive patterns or traces, as well as the substrate, which is usually made of a glass epoxy material. For example, a basic PCB can be divided into 4,6 or 8 signal layers, with the most common being 4- and 6-layer PCBs.As the name implies, PCB patterns are made from printed components, printed circuits, or a combination of both. The conductive pattern is printed or etched onto insulating epoxy glass according to a predetermined design.
How are PCBs used?
PCBs can be customized for use in electronic devices such as televisions and radios, cell phones, cameras, and computer components such as motherboards and graphics cards.PCBs are also used in the manufacture of lighting equipment, medical equipment, the automotive industry, and most industrial machinery.
PCBs are an essential structure in equipment because they support electronic components and are used as the electrical connections for the components.The unique features of PCBs can be summarized as follows:
High-density wiring, lightweight, and small in size, which is ideal for the miniaturization of the electronic equipment under discussion
Due to the graphic consistency and repeatability, PBCs save equipment maintenance, debugging and inspection time.
Its production can be automated to reduce the cost of electronic equipment
Types of PCBs
The forms of PBCs are as follows:
1. Single-layer PCB
Also known as a single-side PCB, this is the simplest and most commonly used PCB in most electronic equipment because it is easy to design and produce. A single-layer PCB is coated with a layer of conductive material, usually copper. A solder mask is used to protect the PCB from oxidation. The components of the PCB are screen printed. This type of PCB is used in low-cost but mass-produced applications such as printers, radios and calculators.
2. Double Layer PCB
This type of PCB, also known as a double sided PCB, has a layer of conductive material, usually copper, on both the top and bottom of the board. The main advantage of this type of PCB over its single-sided counterpart is the increased flexibility and reduced size, making it a compact circuit. It is commonly used in industrial controls, UPS systems, converters, telephones, power monitoring units, amplifiers and HVAC applications.
3. Multilayer PCB
This type of PCB comes with more than two copper conducting layers. The board is held in place by sandwiching glue between the insulating layers to ensure that the circuit is not damaged by overheating. It is used in complex applications such as satellite systems, GPS technology, file servers, data storage devices and medical equipment.
Other types of PCBs include Flexible PCBs, Rigid PCBs and Flexible Rigid PCBs.
PCBA - Printed Circuit Board Assemblies
An acronym for Printed Circuit Boards + Assemblies, PCBA is the entire process of passing unpopulated PCB boards through plated-through-hole (PTH) and surface-mount technology (SMT) processes. These processes allow for the placement and soldering of all electronic components onto a blank PCB and include solder paste printing, component placement, manual, wave or reflow soldering and various forms of QC inspection.
Components of a PCBA
During the assembly process, empty PCBs are filled or populated with electronic components to form functional printed circuit assemblies (PCAs) or PCBAs.Using through-hole technology, electronic components are mounted in holes surrounded by conductive pads. Using SMT, the components are placed on the PCB to ensure that the pins are aligned with the conductive pads. When electronic components are secured to either side of the board, the components on one side of the board must be glued to the board before soldering.
Populated PCBA boards can be tested using one of the following methods:
With the power turned off, the board can be inspected visually or with an automated optical inspection tool.
After power is turned off, an analog signature analysis can be performed. This analysis is called a "power-down test".
When powered on, in-circuit testing is performed
Finally, functional testing can be performed to determine if the PCB is performing as designed.
From the description above, we can determine whether PCBA refers to the processing flow or the entire circuit board, while PCB refers to an empty printed circuit board without electronic components. Typically, a PCB is a bare board, while a PCBA is a finished board.