**REQUIREMENTS**: Suppose I have the requirement of a power source with very high current rating of 5A and 6V but lighter in weight. Also we can’t have a supply of 220 V to the system.

**SELECTION**:

- As we can’t have a 220V, hence we can’t design the power supply our self by transforming AC to DC. Hence I need to use batteries.
- It should be secondary battery so that we can recharge it.
- According to above said specification I select NiMH battery which have cell voltage 1.2V and 2700 mAh current rating. It can be recharge and weight of the battery is 33 gram. This battery is generally used in cameras. For 6V supply , I connect 5 battery in series.

1.2 * 5 = 6.0 V

And two sets of battery are connected in parallel then current will be

2700*2700 = 5400 mAh

Total number of battery is 10. So the total weight of battery is

33* 10 = 330 gram