Garrett metal detectors primarily work using Very Low Frequency (VLF) technology, employing two coils to detect metal objects.
Here's a breakdown of the process:
VLF Technology Explained
VLF metal detectors rely on electromagnetic fields to identify metallic targets. The key components and processes involved include:
- Transmitter Coil: This coil generates an electromagnetic field that radiates into the ground. This field operates at a specific frequency.
- Receiver Coil: This coil constantly monitors the electromagnetic field produced by the transmitter coil.
- Electromagnetic Field Interaction: When the electromagnetic field generated by the transmitter coil encounters a metallic object, it induces a current within the object, creating its own, secondary electromagnetic field.
- Signal Detection: The receiver coil detects changes or distortions in the original electromagnetic field caused by the secondary field from the metallic object.
- Signal Processing: The detector's internal circuitry analyzes the changes detected by the receiver coil. This analysis helps determine the presence, size, depth, and potentially the type of metal.
- Audio/Visual Indication: Based on the signal processing, the detector provides an audio signal (tone) and/or a visual display indicating the presence of a metal object.
The Role of Frequency
The operating frequency of the VLF metal detector plays a crucial role in its performance. Different frequencies are better suited for detecting different types and sizes of metal objects. Lower frequencies tend to be better at detecting larger and more conductive objects at greater depths, while higher frequencies are typically more sensitive to smaller objects and may be better for detecting gold or other less conductive metals.
Example Scenario
Imagine swinging a Garrett metal detector over a park. The transmitter coil sends out an electromagnetic field. If this field encounters a buried coin, the coin becomes energized and emits its own electromagnetic field. The receiver coil senses this disruption in the initial field, signaling the detector to alert the user to the presence of the coin.
