The HI-3637 VLF (very-low frequency) Magnetic Field Meter measures magnetic field flux density in the frequency range of 2 kHz to 400 kHz. The capabilities of this instrument are designed to conform to the guidelines issued recently in Sweden—as well as the IEEE P-1140 protocol—for measuring VLF magnetic fields produced by video display terminals (VDTs). Applications for this versatile meter range from VDTs and computer monitors to high current factory locations. The HI-3637 is a self-contained three-axis flux density meter designed to respond to either sinusoidal or complex magnetic field waveforms, such as those produced by the vertical deflection system of a VDT. The meter circuit utilizes a microprocessor to continually compute the root-mean-square (RMS) value of magnetic field flux density and display it directly on an analog meter, allowing quick assessment of the actual flux density value. The size of the instrumentation/readout package was chosen for two reasons. The first is to allow for two layers of electric and magnetic shielding in addition to the outer housing. The second is to allow for hand held operation. This portability makes the HI-3637 particularly useful in surveying the magnetic field flux density distribution over a large area in a short amount of time. The probe sensor array consists of three mutually orthogonal multi-turn loops connected to the instrumentation/readout package via a 1.5 meter cable. Readings are independent of probe orientation. The probe is electrically shielded, making the HI-3637 immune to most electric field effects. The HI-3637 has a wide dynamic measurement range: 4 nT to 400 ¿iT (100 dB). This makes the HI-3637 convenient for finding VLF magnetic field distributions in any application. The supplied alternate panel label converts the meter scale to Gauss (0.04 mG to 4 G). The optional XI00 probe shifts the measurement range to 400 nT to 40 mT (6 mG to 400 G). An optional kit converts the HI-3637 to indicate fields in field strength units of amps/meter (A/m).