CIS CIS PCB Design & Fabrication Standards 3

Question 1

What is the primary purpose of solder mask on a PCB?

Accepted Answer

To protect copper traces from oxidation and prevent solder bridging

Answer

To improve thermal conductivity between layers

Answer

To increase the board's flexural strength

Answer

To act as an adhesive for surface mount components

Question 2

Which test verifies the registration accuracy of drilled holes to their corresponding pads on a PCB?

Accepted Answer

X-ray inspection

Answer

Coupon cross-section analysis

Answer

Peel strength test

Answer

Microsection analysis

Question 3

What does 'impedance stack-up' refer to in multi-layer PCB design?

Accepted Answer

The arrangement of signal, plane, and dielectric layers to achieve target trace impedances

Answer

The total current capacity of all layers combined

Answer

The mechanical thickness distribution of copper layers

Answer

The order in which layers are laminated during fabrication

Question 4

IPC-4101 specifies requirements for which PCB material?

Accepted Answer

Base materials (laminates and prepregs) for rigid PCBs

Answer

Conductive inks and pastes

Answer

Solder alloys for wave soldering

Answer

Conformal coating materials

Question 5

What is 'copper weight' as specified on PCB fabrication drawings?

Accepted Answer

The thickness of copper foil expressed in ounces per square foot

Answer

The total mass of copper in the PCB

Answer

The percentage of the board surface covered by copper

Answer

The purity grade of the copper plating

Question 6

What is the purpose of 'fiducial marks' on a PCB?

Accepted Answer

To serve as optical reference points for automated assembly equipment

Answer

To identify the board revision level

Answer

To indicate the location of test points

Answer

To mark the minimum bend radius for flex circuits