Little Bee is based on an Anisotropic Magneto-Resistive (AMR) magnetic sensor, which gives it performance comparable to current probes based on fluxgate magnetometers and those with hybrid approaches that couple AC current transformers with DC hall effect sensors. But it offers that level of performance at a much lower cost.

The AMR sensor natively senses magnetic fields, producing a voltage proportional to the magnetic field strength. The clip on current sensing attachment enables current sensing by translating the current in a wire into a magnetic field. It consists of a ferrite toroid with an air gap in which the sensor tip rests. The relationship between the current in the wire and the magnetic field in the air gap varies little as the wire moves around the center of the toroid, providing for accurate current sensing despite variations in the test setup.

The output of the AMR sensor is amplified by a low noise, high bandwidth amplifier to provide the correct signal level for oscilloscopes. The amplifier is controlled by a PIC microcontroller, enabling automatic zeroing and offset adjustment as well as gain and bandwidth switching.

Features:

• Adjustable bandwidth (10 MHz and 1 MHz)
• Adjustable gain (1x and 4x)
• SMA Output Connector
• Connects to any standard 1 MΩ impedance oscilloscope input
• Powered by a single AA battery (4 hour battery life)
• Automatic zeroing

Specifications:

• Current sensing:
• Bandwidth: DC - 10 MHz
• Sensitivity: 0.25 Volts/Amp
• Max Current: +/- 5 A
• Noise:
• 3 mA RMS at 10 MHz bandwidth
• 2 mA RMS at 1 MHz bandwidth
• DC Accuracy: +/- 15%
• Insertion Impedance: 100 nH in parallel with 70 Ohms
• Maximum Wire Size
• 4.25 mm unbroken
• 10 mm end fed
• Magnetic Field Sensing:
• Bandwidth: DC - 10 MHz
• Sensitivity: 0.2 Volts/Gauss
• Max Field: +/- 6 Gauss
• Noise:
• 4 mG RMS at 10 MHz bandwidth
• 2.5 mG RMS at 1 MHz bandwidth

Documents:

• GitHub

Package Includes:

• 1 x Little Bee B1 Current Probe