An EMF reader, or electromagnetic field reader, is a device used to measure the strength of electromagnetic fields in the environment. These fields are produced by various sources, including electrical appliances, power lines, and wireless devices. EMF readers can help identify areas with high electromagnetic exposure, which some people believe may have health implications. There are different types of EMF readers, including analog and digital models. Analog EMF readers use a needle gauge to indicate field strength, while digital models provide numerical readings. Many users employ these devices for personal safety, environmental monitoring, or paranormal investigations, as some believe they can detect ghosts or spirits.