In electromagnetism, Fleming's right-hand rule (for generators) shows the direction of induced current when a

conductor Conductor or conduction may refer to: Music * Conductor (music), a person who leads a musical ensemble, such as an orchestra. * ''Conductor'' (album), an album by indie rock band The Comas * Conduction, a type of structured free improvisation ...

attached to a circuit moves in a

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

. It can be used to determine the direction of current in a generator's windings. When a conductor such as a wire attached to a circuit moves through a magnetic field, an

electric current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving pa ...

is induced in the wire due to

Faraday's law of induction Faraday's law of induction (briefly, Faraday's law) is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (emf)—a phenomenon known as electromagnetic inducti ...

. The current in the wire can have two possible directions. Fleming's right-hand rule gives which direction the current flows. The right hand is held with the

thumb The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb ...

, index finger and middle finger mutually perpendicular to each other (at right angles), as shown in the diagram.{{Cite book, title=Hughes Electrical & Electronic Technology, last=Hughes, first=Edward, date=5 April 2016, publisher=Pearson Education Limited, isbn=978-1-292-09304-8, edition=12th, pages=145 * The thumb is pointed in the direction of the motion of the conductor relative to the magnetic field. * The first finger is pointed in the direction of the magnetic field. By convention, it's the direction from North to South magnetic pole. * Then the second finger represents the direction of the induced or generated current within the conductor (from + to −, the terminal with lower electric potential to the terminal with higher electric potential, as in a voltage source) The bolded letters in the directions above give a mnemonic way to remember the order. Another mnemonic for remembering the rule is the initialism "FBI", standing for Force (or otherwise motion), B the symbol for the magnetic field, and I the symbol for current. The subsequent letters correspond to subsequent fingers, counting from the top: thumb → F; first finger → B; second finger → I. There is also a

Fleming's left-hand rule Fleming's left-hand rule for electric motors is one of a pair of visual mnemonics, the other being Fleming's right-hand rule (for generators). They were originated by John Ambrose Fleming, in the late 19th century, as a simple way of working out ...

(for electric motors). The appropriately handed rule can be recalled from the letter "g", which is in "right" and "generator". These mnemonics are named after British engineer John Ambrose Fleming, who invented them. An equivalent version of Fleming's right-hand rule is th
left-hand palm rule

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Diagrams and exercises
Science mnemonics Electromagnetism zh:佛來明右手定則