Question
Which of the following is a reason to use shielded wire?
Answer Options
- A) To decrease the resistance of DC power connections
- B) To increase the current carrying capability of the wire
- C) To prevent coupling of unwanted signals to or from the wire
- D) To couple the wire to other signals
Correct Answer: C
Explanation
Shielded wire is cable that has one or more insulated conductors covered by a braided metal mesh (the shield) before the outer jacket. The primary purpose of this shield is to act as an electrical barrier against outside interference.
This is used to prevent coupling of unwanted signals to or from the wire, which is an effect called electromagnetic interference (EMI) or RFI. The shield is typically grounded, diverting any external noise picked up or any internal signal radiated (e.g., audio) harmlessly to ground.
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