Whether hunting ghosts or checking a house’s electrical currents, an electromagnetic field meter (EMF meter) is the tool of choice. EMF meters measure AC and DC currents, or fields of electricity, within a certain area. The sensitivity of the tool can vary by model and manufacturer, but most can measure a field of electromagnetic activity between 60 and 50 hertz (Hz). Other EMF detection meters can detect fields as low as 20 Hz, although these are costly and generally only utilized in the fields of scientific research.
There are two basic EMF meter varieties, analog and digital. An analog EMF meter allows the user to read the results as they occur on a field that is marked by different lines and measurements. A digital EMF meter displays the results on a digital screen. Each has its own distinct advantages, with proponents of either type claiming that their chosen EMF meter is more accurate. Within these two types, there are myriad features available to the consumer, including lights that flash to signal a sudden change in electromagnetic fields, or audio noises such as chirps and beeps to indicate the same.
Outside of scientific research, electrical work and home improvement, EMF meters have grown in popularity in the pseudoscience of paranormal investigations. Although widely contested by many, it is the belief of those within this field that when a ghost or spirit is present, electromagnetic fields will change in frequency, or, more simply put, there will be a sudden spike or jolt of energy. This is the apparent reasoning behind the common sensation of hairs rising on the back of someone’s neck--that a change in the electrical currents of the air reacts with the body's own built-in sensors. As EMF meter paranormal use rises, consumers are finding that the overall cost of basic models drops, due to the rapid increase in popularity.
Detection of electrical fields with an EMF meter can also vary depending upon the variety used. Some can only analyze the change in electromagnetic fields over time, or electromagnetic fields generated from manmade sources, or AC currents. Other types can measure natural wavelengths in the earth's magnetic field, also known as DC currents. Some EMF meters can measure both. Some people prefer one or the other, while serious paranormal hobbyists or home improvement buffs find it helpful to have a meter that can read both.