*Question G4C08:
Which of the following would reduce RF interference caused by common-mode current on an audio cable?*  

*Correct Answer is  A: Place a ferrite choke on the cable*  

### AI Response: (may contain errors)  

To reduce RF interference caused by common-mode current on an audio cable, the correct approach is:

### Correct Answer: A: Place a ferrite choke on the cable

1. **Why the correct answer is correct:**
   - A ferrite choke is used to suppress common-mode currents by increasing the impedance of the cable at RF frequencies. This helps to block or reduce the unwanted RF signals that are traveling along the cable, thus minimizing interference.

2. **Why the other choices are incorrect:**
   - **B: Connect the center conductor to the shield of all cables to short circuit the RFI signal**
     - This would short-circuit the audio signal itself, not just the RF interference, leading to loss of the desired audio signal.
   - **C: Ground the center conductor of the audio cable causing the interference**
     - Grounding the center conductor would also short the audio signal, effectively silencing it, which is not a desirable outcome.
   - **D: Add an additional insulating jacket to the cable**
     - Adding insulation does not affect RF interference. Insulation is meant to prevent electrical contact, not to block RF signals.

### Useful Concepts:
- **Common-Mode Current:** This is the current that flows in the same direction on all conductors of a cable. It can cause interference when it couples into sensitive circuits.
- **Ferrite Choke:** A passive device that increases the impedance of a cable to RF signals, effectively reducing the amplitude of common-mode currents.

By using a ferrite choke, you can effectively reduce RF interference without disrupting the intended audio signal.