title: FBI mnemonics
text: # FBI mnemonics
  
  The various FBI mnemonics (for electric motors) show the direction of the force on a conductor carrying a current in a magnetic field as predicted by Fleming's left hand rule for motors and Faraday's law of induction.
  
  Other mnemonics exist that use a right hand rule for predicting resulting motion from a preexisting current and field.
  
  ## Configuration, using the left hand
  
  ### 'FBI'
  
  The left hand is held with the thumb, first finger and second finger mutually at right angles.
  
  * The Thumb represents F - Thrust (or resulting Motion).
  * The First finger represents B - Field.
  * The Second finger represents I or V - Current (in the classical direction, from positive to negative).
  
  ## Configuration, using the right hand
  
  Other sources use the right hand to predict force, though the fingers used vary:
  
  ### 'FIB'
  
  * Thumb = F ("thrust")
  * Index finger = I or V
  * Middle finger ("Birdie") = B
  
  ### 'IBF'
  
  In this alternative, some versions recommend not extending the middle finger, but instead imagining the force coming from the palm of the hand.
  
  * Thumb = I or V
  * Index finger = B
  * Middle finger = F
  
  ## Other frequently confused rules
  
  ### Prediction of direction of field ('B')
  
  The rules above are usually used to predict 'F' based upon 'B' and 'I' - the force on a moving charge when moving through a field, whether or not the charge is carried in a wire. However, this rule should not be confused with a different right hand grip rule for the prediction of the direction of a field ('B') produced by current ('I') traveling through a wire.
  
  ## Symmetry
  
  | Vector | Left-Motor or Right-Generator | Left-Motor or Right-Generator | Left-Motor or Right-Generator | Right-Motor or Left-Generator | Right-Motor or Left-Generator | Right-Motor or Left-Generator |
  | - | - | - | - | - | - | - |
  | B or Field | First or Index | Thumb | Fingers or Palm | First or Index | Thumb | Fingers or Palm |
  | I or Current (+ to - flow) | Fingers or Palm | First or Index | Thumb | Thumb | Fingers or Palm | First or Index |
  | Force, Motion, or Thrust | Thumb | Fingers or Palm | First or Index | Fingers or Palm | First or Index | Thumb |
  