A DC generator works on the principle of:

• A DC generator works on the principle of Electro Magnetic Induction.
• When a DC current passes through a long straight conductor a magnetizing force and a static magnetic field are developed around it.
• If the wire is then wound into a coil, the magnetic field is greatly intensified producing a static magnetic field around itself and forming the shape of a bar magnet giving a distinct North and South pole.
• Then by either moving the wire or changing the magnetic field a voltage and current can be induced within the coil and this process is known as Electromagnetic Induction, which is the basic principle of operation of DC generators.

Faraday’s first law of electromagnetic induction states that whenever a conductor is placed in a varying magnetic field, emf is induced which is called induced emf. If the conductor circuit is closed, the current will also circulate through the circuit and this current is called induced current.

Faraday's second law of electromagnetic induction states that the magnitude of emf induced in the coil is equal to the rate of change of flux that linkages with the coil. The flux linkage of the coil is the product of number of turns in the coil and flux associated with the coil.

These laws are related to the emf of a generator.