Time varying magnetic field safety probe

A passive safety probe for placement in a time varying magnetic field to alert personnel when the power density of high intensity electromagnetic fields reach and exceed applicable personnel safety limits. The probe senses the magnetic field present with a loop antenna. The loop antenna produces a voltage output in response to the magnetic field. The output voltage is linearized by a frequency dependent filter and rectified to provide a direct current output which is subsequently coupled to an attention getting indicating means such as a light emitting diode and/or a horn. When detected field voltage exceeds the threshold of the indicating means, a visual or audible response occurs, indicating that safe field levels have been exceeded.