Question and Answer

Some Basic Questions & Answers Related To Printed Circuit Board -PCB

Q1. What does pcb mean?

A. PCB stands for Printed Circuit Board. It is a copper clad board that is etched to form the desired circuit and drilled, if necessary. Components are placed on the board and soldered to form an assembly.

Q2. How to make a pcb?

A. PCBs are made by etching copper clad boards. First it is necessary to decide on the schematic diagram to be used. A circuit layout is them prepared based on the schematic. The layout is them transferred on to the copper clad board, and all unwanted copper is etched away. If necessary, the board is drilled, and a protection of green solder mask is added.

Q3. What is pcb chemical?

A. PCB chemical is used for etching. It reacts with the unwanted copper on the board and removes it from the surface of the board.

Q4. What is a pcb assembler?

A. PCB assembler is a pick-and-place machine for assembling printed circuit boards. The machine picks up the tiny surface mount components individually from their packaging and places them on the board with the correct orientation and positional accuracy.

Q5. How to solder pcb?

A. PCBs can be soldered by soldering irons, hot air soldering gun, wave soldering machines, or reflow soldering machines. All the machines produce heat for melting solder to bond the components to the board.

Q6. How to design a pcb?

A. PCBs are designed on computers with PCB CAD software. First, a schematic diagram is prepared that shows the entire circuit. Depending on the components used, footprints and placed and arranged properly. Tracks are then routed to interconnect the components according to the schematic. Gerber files are prepared from the layout and sent to the PCB manufacturer, who fabricates the PCB.

Q7. How to clean pcb?

A. De-ionized water is the best solution for cleaning PCBs.

Q8. How to remove solder from pcb?

A. Use braided copper wire or manual solder pump and soldering iron, or hot-air solder remover. The soldering iron melts the solder, and it can be removed by the braided copper wire or the manual solder pump. Hot-air solder remover melts the solder and removes it by sucking it away from the board.

Q9. Why pcbcolour is green?

A. PCBs are covered with a green solder mask for protection. The green mask protects the copper tracks from being oxidised and corroded by oxygen in the atmosphere.

Q10. How to drill a pcb?

A. Use a drilling machine and suitable drill bit. For small PCBs, a hand-held drilling machine is enough. Larger PCBs require a CNC drilling machine. For complicated PCBs, laser drilling is a more effective method.

Q11. What is multilayer pcb?

A. A PCB having more than two layers. When it is necessary to fit a large circuit on a small PCB, there is not much space available on the board for routing the tracks. By increasing the number of layers, more routing area is made available, as tracks can be placed on the inner layers also.

Q12. What is pcb assembly process?

A. PCB assembly process includes solder paste deposition, component placement, and reflow soldering. Solder paste is deposited on the PCB pads using a stencil. Surface mount components are them placed on the solder paste using pick and place machines. This assembly is then passed through a reflow machine where hot air melts the solder paste and it bonds the component to the pads on the PCB.

Q13. What is hdipcb?

A. High Density Interconnect printed circuit board. It is a special type of board with fine traces and spaces, and features high component density with laser drilled vias. HDI PCB is essential for complex components like the computer motherboards.

Q14. What is silkscreen pcb?

A. Silkscreen printing allows printing of component designators and other information on the PCB. This is very helpful for the assemblers to know which component is to be placed at a specific location. It is also helpful in deciding the polarity of the component to be placed. The silkscreen provides additional mounting information also.

Q15. How to test pcb?

A. PCB testing can involve the use of Multimeters, testing jigs, or flying leads. With a multimeter one can basically test the PCB for electrical continuity and shorts. Testing jigs and flying leads can test passive components. Functional testing can test the proper functioning of a PCB mounted with components.

Q16. What is pcb designing?

A. PCB designing involves schematic capture, footprint library, component layout, stackup design, and routing.

Q17. How to make connections on pcb?

A. Connections on a PCB are already made with the copper tracks present on it. If two PCBs are to be interconnected, it is best to use a connector and wire assembly.

Q18. Which PCB design software is the best?

A1. Protel (Altium Designer) — May be expensive

MultiSIm / Ultiboard

Proteus

CADSoft Eagle

Q19. Where PCB is used?

A. In all equipment that use electronic components, especially, surface mount components.

Q20. How PCB is made?

A. PCBs are made from copper clad laminates. These have copper foils on both sides of the laminate, which also acts as an insulator. The fabricator transfers the circuit layout to the copper foils, drills holes for vias, and etches away the unwanted copper. After washing the board, they electroplate to form the vias. Then they cover the copper tracks with a solder mask layer to protect them from being tarnished. The pads where the components will be soldered are not covered by solder mask, but by surface finish. This helps to protect the exposed copper pads and, at the same time, allows soldering also.

Q21. How PCB works?

A. Assemblers solder SMD components to copper pads and copper traces on both sides of the board to connect them according to the schematic design. Vias interconnect two sides of the circuit electrically. When the user applies power to the PCB, all the components start to work according to their function in the schematic.

Q22. How PCB is designed?

A. A designer prepares the schematic according to the way they want the circuit to function. They assign footprints to each component and generate a net list. Using the net list and the footprints, the designer then prepares a layout of the components within the boundary of the PCB. They use a PCB CAD software tool to route each net between the components following a set of rules.Once the layout is ready, the designer transfers the design files to a standard Gerber format and sends these to the fabricator.

Q23. How PCB board works?

A. Power and signals supplied to the PCB board by the user enables it to function properly. The board has electronic components that act as passive or active devices to control the power and signals. Copper traces on the board connect the electronic components, supplying them with power and signals. Vias on the board allow electrical connections from one side of the board to the other.

Q24. How PCB Vias are made?

A. The fabricator drills holes in the PCB for placement of vias. Then they electroplate the board to create the barrel of the via. The barrel interconnects pads on the two sides of the PCB, connecting them electrically.

Q25. What PCB stands for?

A8. PCB is an acronym for Printed Circuit Board.

Q26. What PCB contains?

A. A PCB contains the board on which the assembler mounts surface mount or through hole components and solders them.

Q27. Why PCB is Green?

A. The green color is because of the solder mask the fabricators put on the PCB to protect the copper traces from tarnishing. Although the common color of the solder mask is usually green, the fabricator may use other colors also, like white, red, and blue.

Q28. Why PCB is required?

A. An equipment may contain over 1,000 electronic components requiring connections in a very specif way to allow them to function properly. A PCB helps by allowing the assembler to mount the components in a specific way, and to solder them in place to keep them anchored. The user can easily test the board if it is not functioning in the right way. A PCB increases the reliability of the equipment substantially.