CAD CAD Specialist Electrical and Electronics Design 2

Question 1

What is the purpose of a 'Design Rule Check' (DRC) in PCB CAD software?

Accepted Answer

Checks that physical layout constraints such as clearances and trace widths are satisfied

Answer

Verifies component values match the schematic BOM

Answer

Confirms that all components have 3D models assigned

Answer

Validates the BOM against live supplier databases

Question 2

In PCB design, what is a 'via'?

Accepted Answer

A plated hole that electrically connects copper traces on different PCB layers

Answer

A copper pour limited to the top copper layer

Answer

A non-electrical component mounting hole

Answer

A fiducial mark used for automated optical inspection

Question 3

Why is 'controlled impedance' important in high-speed PCB design?

Accepted Answer

It matches trace impedance to source and load impedance to preserve signal integrity

Answer

It minimizes the total number of vias required

Answer

It reduces overall board dimensions

Answer

It prevents copper delamination during solder reflow

Question 4

What does a 'copper pour' (flood fill) accomplish on a PCB layer?

Accepted Answer

Fills unused board areas with copper connected to a net — typically ground

Answer

Adds a solder mask coating over exposed copper

Answer

Increases the board's dielectric constant

Answer

Creates thermal relief patterns around component pads

Question 5

In Gerber-based PCB fabrication output, what information does the NC drill file contain?

Accepted Answer

X,Y coordinates and diameters of all holes to be drilled

Answer

Artwork for all copper layers in Gerber RS-274X format

Answer

Silkscreen legend artwork for component identifiers

Answer

Board outline dimensions in mechanical CAD format

Question 6

What is the primary purpose of a 'keepout zone' in PCB layout?

Accepted Answer

Restricts component placement, copper routing, or both within a defined area

Answer

Marks recommended locations for fiducial alignment marks

Answer

Defines the board outline path for the router

Answer

Specifies areas where silkscreen ink is not allowed

Question 7

Which PCB layer prevents solder from adhering to areas between pads during reflow soldering?

Accepted Answer

Solder mask layer

Answer

Silkscreen (legend) layer

Answer

Solder paste stencil layer

Answer

Copper ground plane layer