PCB Professional Standards & Competencies 3 — Questions and Answers
Question 1: What is the primary purpose of an Engineering Change Order (ECO) in PCB design?
- To order new components
- To formally document and authorize design changes after release (Correct answer)
- To update the cost estimate
- To notify customers of delays
Correct answer: To formally document and authorize design changes after release
An ECO provides a controlled mechanism to document, review, approve, and implement design changes to a released product.
Question 2: Which UL standard is commonly associated with flammability ratings for PCB base materials?
- UL 508
- UL 94 (Correct answer)
- UL 1449
- UL 60950
Correct answer: UL 94
UL 94 defines flammability ratings (V-0, V-1, V-2, HB) for plastics including PCB laminate materials.
Question 3: In a professional PCB design workflow, who typically has authority to approve a design for release to manufacturing?
- Only the PCB designer
- A designated approver such as a project engineer or design manager per the company's controlled process (Correct answer)
- The PCB fabricator
- The sales team
Correct answer: A designated approver such as a project engineer or design manager per the company's controlled process
Controlled release processes require designated approvers with authority defined by company procedure, not unilateral designer action.
Question 4: What information is typically included in a PCB stackup document?
- Layer order, dielectric thickness, material type, and copper weight per layer (Correct answer)
- Component placement coordinates only
- Gerber file names
- Solder paste stencil aperture sizes
Correct answer: Layer order, dielectric thickness, material type, and copper weight per layer
A stackup document specifies each layer's material, thickness, copper weight, and order to guide the fabricator in building the correct laminate structure.
Question 5: A colleague asks you to skip the peer review step to meet a deadline. The professional response is to:
- Skip the review to keep the schedule
- Explain the risk of skipping review and escalate the schedule pressure to management (Correct answer)
- Complete the review yourself without a second reviewer
- Blame the delay on component availability
Correct answer: Explain the risk of skipping review and escalate the schedule pressure to management
Professional ethics require communicating risk honestly and escalating schedule conflicts rather than silently bypassing quality controls.
Question 6: What does the term 'design freeze' mean in a PCB project context?
- The CAD tool has crashed
- A formal point at which no further changes are permitted without an ECO (Correct answer)
- The board has been placed in cold storage
- All components are backordered
Correct answer: A formal point at which no further changes are permitted without an ECO
Design freeze marks the point where the design is locked for release; any subsequent changes require a formal ECO to maintain control.
Question 7: Which metric is most relevant for assessing a PCB designer's adherence to professional standards?
- Number of boards designed per month
- Defect escape rate and number of design re-spins due to errors (Correct answer)
- Speed of schematic entry
- Number of components on the largest board
Correct answer: Defect escape rate and number of design re-spins due to errors
Defect escape rate and re-spin frequency directly reflect design quality and adherence to standards and review processes.
PCB Professional Standards & Competencies 3
What is the primary purpose of an Engineering Change Order (ECO) in PCB design?