The E-meter, introduced during the Hubbard College lectures, was designed by Dianeticist Volney Mathison. It resembles a Wheatstone's Bridge very closely, and can be used as a lie detector (like in police polygraphs in the US). In Scientology, the Pre-clear (or person being audited in plain english) takes the soup-can-like electrodes, one in each hand, and they are then "audited", using not Dianetics auditing, but Scientology techniques. Often, the end result of a session is determined to be when the needle "F/N's" (floating needle).

According to Hubbard, any positive change in skin resistance noted by the E-meter is the result of the presence of the "mental mass" of an engram. Thus, engrams can be detected. Likewise, a gross absence of resistance is taken as meaning an engram (or its charge) has been dissipated (or "flattened"). The reactions of the subject to the questions asked (actually as well as in terms of any E-meter activity) and the answers themselves are recorded by the auditor. During the session, the subject sees neither the E-meter nor the comments recorded by the auditor, and is normally never allowed to see them. It (the E-meter) is used purely as a lie detector in "security checking" and "ethics cycles".

It has been estimated by several outside observers of the scene that a functioning E-meter could be very easily built by anyone capable of using a soldering iron for approximately $100 (or less), minus, of course, the "swoopy" case. In spite of this, a new approved E-meter retails for upwards of (US)$3500 and it is recommended each auditor have TWO (in case one fails in session.) I don't know about YOU, but if I had a failure (in session or not) of a device I'd paid upwards of $3500 for, I'd probably have some really pithy things to say, and likely wouldn't be buying another!

-- Adapted from the Scientology.FAQ

However, the Church claims:

The Hubbard Electrometer is a religious artifact used in the Church confessional. It in itself, does nothing, and is used by Ministers only, to assist parishioners in locating areas of spiritual distress or travail.

-- To the Reader, Handbook for Preclears and other documents.

Anyway, enough about the E-Meter, there's plenty information out there about it, including circuit diagrams posted regularly to alt.religion.scientology.

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