E-Meter is a shortened term for electropsychometer. It is a religious artifact used as a spiritual guide in auditing. It is for use only by a Scientology minister or a Scientology minister-in-training to help the preclear locate and confront areas of spiritual upset.

In itself, the E-Meter does nothing. It is an electronic instrument that measures mental state and change of state in individuals and assists the precision and speed of auditing. The E-Meter is not intended or effective for the diagnosis, treatment or prevention of any disease.

The book Understanding the E-Meter offers a simple explanation of how the E-Meter works and what it actually measures. In order to understand what the E-Meter does, it is necessary to understand some basic Scientology concepts.

There are three basic parts of man — mind, body and thetan. The thetan is an immortal spiritual being — the individual himself. He (the thetan) inhabits a body, which is a carbon-oxygen machine. He has a mind, which is a collection of mental image pictures he has created. These pictures have weight and mass and can impinge on the person when he is emotionally upset.

This is what makes the E-Meter read — the impingement of such pictures against the body. The E-Meter puts a very small electrical current (approximately one-and-a-half volts) through the body. This is about the same amount of current as in the average battery-powered wristwatch. When a person thinks a thought, looks at a picture, reexperiences an incident or when he shifts some part of the pictures in his mind, he is moving and changing actual mental mass and energy. These changes in the person’s mind affect the tiny flow of electrical energy generated by the E-Meter, which causes the needle on its dial to move.

The E-Meter thus measures changes that are caused by the spiritual being in his own mind (i.e., the movement of mental masses around him) and in this capacity, it is a religious artifact.

The E-Meter is used to help the individual who is being audited uncover truth. By locating areas of mental or spiritual trauma, the E-Meter helps both the auditor and the preclear locate exactly what to address in auditing.