Voltage & current supply in India is different than the rest of the world. The voltage in India is 220 Volts, alternating at 50 cycles per second. If you use the device that do not accept 240 volts at 50 hertz, then you will be required to carry a voltage converter. Or if you wish to use any electronic devices from the United States or any country with 110 Volt currency, you'll need a voltage converter and plug adapter.
In India basically three types of voltage converters that are available and adaptable to the Indian voltage.
Resistor-network converters : 50-1600 Watts. Can be used for appliances like hair dryers and irons. You can use them for short periods only and they are not ideal for digital devices.
Transformers : 50-100 Watts it can be used continuously for items like battery chargers, laptop, computers, radios, cameras, MP3 players and camcorders. Drawback of this is the low wattage and heavy weight.
Combination converters: Has a combination voltage of resistor network and transformers. One can switch from one mode to another by a switch provided for this purpose.
Outlets in India generally accept the following types of plug:
-> 2 round pins
-> 3 round pins arranged in a triangle
People coming from countries with 230 Volt currency (such as Australia, Europe, and the UK) only require a plug adapter for their appliances.