Draw the diagram of a DC generator. Then explain as to how the DC current is obtained.

Explanation

(C) Electric Generator (DC)
A generator which converts mechanical energy into electrical energy in the form of direct current is called as D.C. generator.
Construction: The main components of D.C. generator are:
i. Rectangular coil (ABCD): It consists of a large number of turns of insulated copper wire wound on an iron core in rectangular shape.
ii. Strong magnets: The coil is placed between the two pole pieces (N and S) of a strong magnet that produces a strong magnetic field.
(iii.) Split ring: It consists of two halves of a metallic ring to which the ends of the coil are connected.
iv. Brushes: Carbon brushes `(B_(1) and B_(2))` are used to press the rings.
v. Axle: The function of axle is to rotate with the coil.

Working:
i. When the axle is rotated with the help of a machine from outside, the coil ABCD starts rotating.
ii. On rotating the axle, the branch AB move upwards and branch CD move downwards and coil ABCD rotates clockwise.
iii. According to Fleming's right hand rule, electric current flows in the direction `ArarrBrarrCrarrD`.
Therefore, current flows in the external circuit through galvanometer.
iv. After half rotation, the branch AB and CD exchange their position and the induced current flows as `Drarr CrarrBrarrA`.
v. Since, the branch which is moving upwards is always in contact with brush B1 and the branch which is moving downwards is always in contact with brush `B_(2)`, current flows in the same direction in the external circuit, thereby producing direct current.