Current also results when a complete circuit is connected to  that voltage. Electrical power is produced when there is both  electrical pressure E (EMF) and current (I). Power = Current  ×  Voltage (P = I  ×  E) It is the relative motion between a conductor and a magnetic  field that causes current to flow in the conductor. Either the  conductor or magnet can be moving or stationary. When a  magnet and its field are moved through a coiled conductor,  as shown in  Figure 9-7 , a DC voltage with a specific polarity  is produced. The polarity of this voltage depends on the  direction in which the magnet is moved and the position of  the north and south poles of the magnetic field. The generator  left-hand rule can be used to determine the direction of   current flow within the conductor.  [Figure 9-8]  Of course,  the direction of current flow is a function of the polarity of  the voltage induced in to the conductor.  In practice, producing voltage/current using the process  of electromagnetic induction requires a rotating machine.  Generally speaking, on all aircraft, a generator or alternator  employs the principles of electromagnetic induction to create  electrical power for the aircraft. Either the magnetic field  can rotate or the conductor can rotate.  [Figure 9-9]  The  rotating component is driven by a mechanical device, such  as an aircraft engine. During the process of electromagnetic induction, the value of  the induced voltage/current depends on three basic factors:  1.  Number of turns in the conductor coil (more loops  equals greater induced voltage) S N S N S N Motion of magnet Galvanometer A B C Motion of magnet Coil Magnet at rest I I I I N S A B S N Induced EMF Flux forward Inducted EMF Conductor  moved up Figure 9-8.  An application of the generator left-hand rule. Figure 9-7.  Inducing a current flow. Figure 9-9.  Voltage induced in a loop. 9-6