Description
Other details:
- Target Micro Scan metal detectors use a balanced, three-coil, system to detect small particles of non-ferrous and stainless steel
- The coils are wound on a non-metallic frame, each parallel with the other
- The centre coil is connected to a high-frequency radio transmitter
- Coils on either side of the transmitter coil are receivers
- As these two coils are identical and placed the same distance from the transmitter, they receive the same signal and produce an identical output voltage
- When the coils are connected in opposition, the output is cancelled, resulting in a zero value
- A schematic of the coil configuration is shown in figure 1
- When a particle of metal passes through the coils of a metal detector, the high-frequency field is disturbed under one coil, changing the voltage by a few micro volts
- The state of balance is lost and the output from the coils is no longer zero
- It is this phenomenon that is used to detect metal.
