Rule 104 - Preliminary Questions(a) In General. The court must decide any preliminary question about whether a witness is qualified, a privilege exists, or evidence is admissible. In so deciding, the court is not bound by evidence rules, except those on privilege.(b) Relevance That Depends on a Fact. When the relevance of evidence depends on whether a fact exists, proof must be introduced sufficient to support a finding that the fact does exist. The court may admit the proposed evidence on the condition that the proof be introduced later.(c) Conducting a Hearing So That the Jury Cannot Hear It. The court must conduct any hearing on a preliminary question so that the jury cannot hear it if: (1) the hearing involves the admissibility of a confession;(2) a defendant in a criminal case is a witness and so requests; or(d) Cross-Examining a Defendant in a Criminal Case. By testifying on a preliminary question, a defendant in a criminal case does not become subject to cross-examination on other issues in the case.(e) Evidence Relevant to Weight and Credibility. This rule does not limit a party's right to introduce before the jury evidence that is relevant to the weight or credibility of other evidence.Advisory Committee Note. The language of this rule has been amended as part of the restyling of the Evidence Rules to make them more easily understood and to make style and terminology consistent throughout the rules. These changes are intended to be stylistic only. There is no intent to change any result in any ruling on evidence admissibility. This rule is the federal rule, verbatim.