The electromagnetic field detectors are capable of detecting electric fields between 0 and 1000 V/m (volts/meter) and magnetic fields up to 1000 milliGauss. In practise the detectors will be looking for fields in the bottom one percent of this range - between 0 and 10 on both scales.

The monitors have been designed to eliminate as much background 'noise' as possible - particularly strong anthropogenic fields that might produce false positive readings -the domestic current is still connected and the house is full of electrical equipment.

It is claimed by 'ghost-hunters' that paranormal events are associated with electromagnetic fields of certain strength - most particularly static magnetic fields between 2 and 7 milliGauss in strength. This is sometimes combined with any indications of electric field over the natural background occurrences of 1 or 2 V/m.

The monitors will be specifically looking for readings in this allegedly significant range, with the aim of assembling a picture of anomalous electromagnetic activity throughout the house and eventually relating this to reports and experiences of a paranormal nature.