You searched for: “e meter
electropsychometer, E-meter (s) (noun)
An electronic device manufactured by the Church of Scientology at their Gold Base production facility: "Known as an "E-meter", the electropsychometer measures changes in the electrical resistance of the human body by inducing a tiny electrical current through it."

"The face of the electropsychometer has a galvanometer that indicates changes in the person's resistance. According to Scientology doctrine, the resistance corresponds to the mental mass and energy of the subject's mind, which changes when the individual thinks of particular mental images or engrams (unconscious, painful memories)."

"These concepts are not validated by other scientists outside of Scientology; the action of the E-meter is more commonly attributed to galvanic skin response, an effect that is used in lie detectors."