Deep Dive: E4A09
The correct answer is A: Minimize the length of the probe's ground connection. Which of the following is good practice when using an oscilloscope probe is to minimize the length of the probe's ground connection. Short ground leads reduce inductance and improve accuracy. For amateur radio operators, this is important for accurate measurements. Understanding this helps when using oscilloscopes.
Why Other Answers Are Wrong
Option B: Incorrect. Never using high-impedance probe on low-impedance circuit isn't necessarily bad practice - minimizing ground length is more important. High-impedance probe isn't the issue. Option C: Incorrect. Never using DC-coupled probe on AC circuit isn't bad practice - DC-coupled probes work fine on AC. DC-coupled isn't the issue. Option D: Incorrect. Since B and C are not necessarily bad practice, 'all of the above' cannot be correct. Only minimizing ground length is the good practice.
Exam Tip
Oscilloscope probe good practice = minimize ground connection length. Think 'P'robe 'G'round = 'P'roperly 'G'rounded (short). Short ground leads reduce inductance and improve accuracy. Not high-impedance probe, not DC-coupled - just minimize ground length.
Memory Aid
Oscilloscope probe good practice = minimize ground connection length. Think 'P'robe 'G'round = 'S'hort. Short ground leads reduce inductance and improve accuracy. Important for accurate measurements.
Real-World Example
Using an oscilloscope probe: Good practice is to minimize the length of the probe's ground connection. Long ground leads add inductance, which can cause ringing and measurement errors. Short ground leads provide better accuracy. This is the good practice - minimize ground connection length.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4A
Reference: 2024-2028 Question Pool · E4 - Amateur Practices
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E4A topic.