Hall Effect Probe
Measure the Magnetic Fields that You Teach
Measures Magnetic Fields of Simple Configurations
Transverse and Radial Sensors
High Sensitivity: 2x10-3 mT (2 microtesla)
TeachSpin Inc. has developed a two-axis Hall Effect Probe with microtesla sensitivity that is capable of measuring the magnetic fields discussed in introductory electricity and magnetism courses at both colleges and secondary schools.
The magnetic field created by the current in a long straight wire is the standard application of Ampere's Law. The axial magnetic field of a current loop is often the textbook's example of the Biot-Savart Law. The 1/r3 dependence of the field of a magnetic dipole and the uniformity of the axial field in a Helmholtz pair are other examples that can be found in the problem section of many texts.
The Hall Effect Probe makes measurements of these "textbook" fields possible and affordable.
TeachSpin's HE1-A Hall Effect Probe is a rugged and versatile device that produces a low impedance output voltage directly proportional to the magnetic field at its sensors. It can measure both the radial and transverse components of the field at a given region of space. It can measure both constant and low frequency alternating magnetic fields. The HE1-A is a high sensitivity device capable of measuring the magnetic field created by a 10 ampere current flowing in a long straight wire at a radial distance of up to one half meter.
The probe has two gain settings that give the instrument a large dynamic range. It has a linear response to better than 0.1% over the entire range. The manual zero adjust allows the operator to set the output voltage to zero in the local ambient Earth's magnetic field. HE1-A has its own power supply that plugs directly into a standard wall outlet of 110VAC. An analog or digital voltmeter is needed to determine the output of the probe. TeachSpin recommends a digital voltmeter capable of measuring millivolts, since the instrument has a maximum sensitivity of about 10-3 mT/mV and a voltage stability of 2mV. The maximum output is +/- 11 volts.
HE1-A is not calibrated. The job of calibration is left as an exercise for the student or it can be done by the teacher. We recommend using a Helmholtz pair, such as the one provided with TeachSpin's "Magnetic Force" since the field is very uniform in the central region between the two coils. Data set 1 is a typical calibration curve using our MF1-A coils. Data set 2 shows the magnetic field as a function of radial distance from a long straight wire carrying 10 amperes of current.
The probe is available with a handsome non-magnetic stand made of hardwood, aluminum and brass components. The probe has a built in ring stand clamp made of aluminum with nylon thumb screws. As with all of TeachSpin's instruments, HE1-A is warranted for two years.
Maximum output: +/- 11 volts
Two sensitivity ranges: x1, x10
Sensitivity 10-2 and 10-3 mT/mV
Stable to +/- 2 mV
Zero offset adjustment
Transverse and radial sensors
Linear on both ranges to better than 0.1%
AC response to 300 Hz, half gain at 100 Hz
Internal power supply
Requires external voltmeter