CIS Study Guide 2026
Everything you need to pass the CIS exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 CIS Exam Format at a Glance
📚 CIS Topics to Study (38)
✍️ Sample CIS Questions & Answers
1. The most common lead-free solder alloy used in SMT reflow soldering per J-STD-006 is:
SAC305 (96.5% tin, 3% silver, 0.5% copper) is the industry-standard lead-free alloy with a melting point of approximately 217–221°C.
2. Which cleanliness test method measures ionic contamination on a PCB assembly after soldering?
The ROSE test (also known as the Omega-meter test) measures ionic contamination by dissolving surface residues in isopropyl alcohol/water and measuring resistivity change.
3. What is 'pad conditioning' during SMT rework?
Pad conditioning involves cleaning residual solder from the pad, re-tinning with fresh solder if needed, and verifying the pad shape and condition before installing a replacement component.
4. An inspector observes a solder bridge between two adjacent SMD pads on a Class 2 assembly. Which of the following best describes the disposition?
Solder bridges between conductors that should not be electrically connected are unconditional defects under IPC-A-610 for all product classes.
5. When performing solderability testing per J-STD-003, what does the wetting balance test measure?
The wetting balance (Meniscograph) test measures the time-force curve as a lead is immersed in solder, quantifying the speed and degree of solder wetting.
6. What hazard does halide contamination (chlorides, bromides) pose to PCB assemblies?
Halide ions (Cl⁻, Br⁻) from flux activators are aggressive corrosion catalysts; if left on the assembly, they absorb moisture and create highly corrosive ionic solutions that accelerate metal corrosion and electrochemical migration.