What are the main types of responses used in general locating?

• A. Peak and Null
• B. Pulse and Echo
• C. Rise and Fall
• D. Peak and Saddle

Answer: (A)

In general locating, you identify buried facilities by how the locator’s reading changes as you sweep over the area. The two main response patterns you rely on are a peak and a null. A peak shows up when the receiver is positioned so the transmitter’s field is strongest directly over the buried line, giving a clear, maximum deflection that points to the line’s center. As you move off that center, the reading drops to a null—near-zero—which occurs on either side due to the geometry of the magnetic field and the coil, helping to confirm the line’s location and symmetry. This peak-and-null behavior is the standard way to pinpoint the centerline and estimate depth, whereas other terms like pulse-and-echo describe different measurement methods (such as time-domain systems) and aren’t the typical indicators used in general locating.