CIS Cheat Sheet 2026

The 30 highest-yield CIS facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the role of a conformal coating in PCB assembly? → To provide electrical insulation and environmental protection
2. Which condition would constitute a defect in conformal coating per IPC-A-610 for Class 2 and Class 3 assemblies? → Exposed conductors or solder connections that are required to be coated
3. Which IPC standard specifically covers the qualification and performance of flexible and rigid-flex printed boards? → IPC-6013
4. During conformal coating application, which types of features MUST typically be masked to prevent coating? → Edge connectors, test points, and adjustable components
5. What is the proper method for removing excess solder from a joint? → Use a solder wick or desoldering pump
6. What causes 'cold solder joints' during hand soldering? → Insufficient heat or movement during solidification
7. How can manufacturers reduce the risk of component damage during transport? → Using ESD-safe packaging and ensuring proper cushioning
8. What is a common method for testing PCB functionality after assembly? → Functional testing to verify performance
9. What is the maximum number of times a through-hole plated barrel may be thermally stressed during rework per IPC-7711? → Four times
10. What color are most standard ESD protective bags and packaging materials? → Pink or metallic shielding (silver/gray)
11. Why is it important to use the correct amount of solder in a joint? → To ensure a reliable connection without shorts or weak joints
12. What does the 'JEDEC' polarity marking on a SOT-23 transistor package typically consist of? → A molded dot or alphanumeric code on the package surface
13. Per IPC-A-610, which condition is allowed for a Class 1 product but not for Class 3 regarding chip component solder joints? → End-cap solder coverage extending only onto the bottom face
14. What is the IPC-A-610 acceptability condition for a solder bridge between two conductors that should not be electrically connected? → A defect for all classes
15. Which packaging material provides BOTH electrostatic shielding AND dissipative properties for transporting ESD-sensitive assemblies? → Metalized shielding bags
16. What is the correct interpretation of a 'target condition' in IPC-A-610? → The ideal, preferred condition showing a high degree of workmanship
17. A wrist strap used for ESD protection should be tested: → Before each use or at the beginning of each shift
18. Which ESD model most closely simulates the discharge from a metal tool or conductive object touching a component pin? → Machine Model (MM)
19. Which IPC standard specifically addresses the qualification and performance requirements for conformal coating materials? → IPC-CC-830
20. What SMT defect is caused by insufficient solder paste and results in an open circuit? → Solder starved joint
21. Per IPC-A-610, which of the following is an acceptable condition for a Class 2 SMT resistor chip component? → Side overhang is 25% of the component width
22. When baking moisture-sensitive components to restore floor life, what must be done after the baking process is complete? → Allow components to cool, then reseal in moisture barrier bags with fresh desiccant
23. What is a 'voiding' defect in solder joints? → Gas pockets trapped inside a solder joint
24. What is the primary function of a component identifier (CID) number? → To ensure correct component usage in assembly
25. What is the best method for preventing ESD when handling sensitive components? → Using an ESD-safe workstation and wrist straps
26. Why is testing crucial in the PCB assembly process? → To verify that the PCB performs correctly and is free from defects
27. What is the primary purpose of proper component identification in electronics? → To ensure components are correctly used and avoid assembly errors
28. What is the approximate melting point difference between eutectic Sn63/Pb37 solder and SAC305 lead-free solder? → Approximately 34°C higher for SAC305 (183°C vs ~217°C)
29. What is ESD and how does it affect electronic components? → It is the discharge of static electricity that can damage components
30. Which ESD control element provides the primary grounding path for operators working at a bench? → ESD wrist strap connected to a common point ground