CAD CAD Specialist Electrical and Electronics Design 1 — Questions and Answers
Question 1: What does a 'net' represent in an electrical schematic?
- A physical wire routed on a PCB
- An electrical connection shared between two or more component pins (Correct answer)
- A ground plane poured across a layer
- A component package footprint
Correct answer: An electrical connection shared between two or more component pins
A net represents an electrical node — a named connection shared by all pins that are electrically joined in the schematic.
Question 2: Which US standard defines graphic symbols used for electrical and electronics schematic diagrams?
- ASME Y14.5
- ISO 128
- ANSI/IEEE 315 (Correct answer)
- IEC 60617
Correct answer: ANSI/IEEE 315
ANSI/IEEE 315 defines the graphic symbols for electrical and electronics diagrams used in US industrial and defense practice.
Question 3: What is a 'block attribute' used for in AutoCAD electrical symbol blocks?
- Setting the display color of a symbol
- Storing variable text such as part numbers or component values within a reusable block (Correct answer)
- Locking a layer from editing
- Defining a hatch fill inside the symbol boundary
Correct answer: Storing variable text such as part numbers or component values within a reusable block
Block attributes store variable text data — such as reference designators, part numbers, or voltage ratings — within a block so each instance can carry unique information.
Question 4: What is a 'ladder diagram' primarily used to document in electrical CAD?
- 3D wire harness routing in an enclosure
- PLC logic for industrial control systems (Correct answer)
- PCB copper trace layouts
- Single-line power distribution topology
Correct answer: PLC logic for industrial control systems
Ladder diagrams document PLC (Programmable Logic Controller) logic, with horizontal rungs showing control elements like contacts, coils, and timers.
Question 5: What does a 'reference designator' (RefDes) identify in an electrical schematic?
- The pin count of a component
- Each unique component instance on a schematic (e.g., R1, C3, U5) (Correct answer)
- The manufacturer's part number
- The voltage rating of the component
Correct answer: Each unique component instance on a schematic (e.g., R1, C3, U5)
A reference designator is a unique alphanumeric label (e.g., R1, C3) that identifies each individual component instance on a schematic.
Question 6: What does 'cross-referencing' accomplish in a multi-sheet electrical schematic set?
- Links component footprints to their 3D models
- Connects wire nets that continue on different sheets by matching labels or connectors (Correct answer)
- Flags duplicate reference designators across sheets
- Exports the bill of materials to a spreadsheet
Correct answer: Connects wire nets that continue on different sheets by matching labels or connectors
Cross-referencing links wire nets or signals that leave one schematic sheet and continue on another by using matching off-page connector symbols or net labels.
Question 7: In an electrical panel layout drawing, what does a 'terminal strip' represent?
- A power bus bar connecting main circuit breakers
- A row of individual terminals used to join wires from different circuits (Correct answer)
- A grounding conductor running along the panel enclosure
- A label strip affixed to the front door of the panel
Correct answer: A row of individual terminals used to join wires from different circuits
A terminal strip is a modular block of individual screw or spring terminals that provides organized connection points for wires entering or leaving an electrical panel.
CAD CAD Specialist Electrical and Electronics Design 1
What does a 'net' represent in an electrical schematic?