The correct answer is option 2 - generator.

A generator is a device that converts mechanical energy into electrical energy. It generally consists of a rotating coil of wire called an armature, which is placed between two magnets. When the armature rotates within the magnetic field created by the magnets, it generates an electric current. This current can then be used to power electrical devices.

Option 1 - motor, is incorrect because a motor is a device that converts electrical energy into mechanical energy. It uses the same principle as a generator but in reverse.

Option 3 - ammeter, is incorrect because an ammeter is a device used to measure electric current flowing through a circuit. It does not generate electric current.

Option 4 - galvanometer, is incorrect because a galvanometer is also a device used to measure electric current. It is sensitive to small currents and is often used as a part of instruments like ammeters and voltmeters.

Therefore, the correct answer is option 2 - generator, as it is the device specifically designed to produce electric current.