POWER FREQUENCY MAGNETIC FIELD INDICATOR Russian patent published in 2012 - IPC G01R33/02 

FIELD: physics.

SUBSTANCE: power frequency magnetic field indicator, having a self-contained power supply, a variable magnetic field sensor consisting of a magnetically conducting core and an inductance coil placed on said core, an ac amplifier, a dc supply voltage resistance divider comprising an variable resistor, and a comparator having two inputs, the first of which is connected to the sliding contact of the variable resistor, and one output, as well as a light signalling device whose input is connected to the output of the comparator, further includes a band-pass filter with bandwidth of 30-70 Hz, a full-wave rectifier and an audio indicator device whose input is connected to the output of the comparator; the inductance coil is connected to the input of the amplifier; the input of the filter is connected to the output of the amplifier; the input of the rectifier is connected to the output of the filter and the second input of the comparator is connected to the output of the rectifier; wherein levels of magnetic field induction at which the light and audio signalling devices switch on are equal to 0.2 mcT and 2 mcT at frequency 50 Hz at the extreme positions of the sliding contact of the variable resistor.

EFFECT: broader functional capabilities of the indicator.

3 cl, 1 dwg