If you are planning to take a camera battery charger or anything else powered by electricity to Papua New Guinea, you may need some, if not all, of the following information:
1. The voltage is 240v
2. The frequency is 50hz
3. The wall plugs are Type I, the ones with diagonal pins, same as Australia's
To get a North Amercian plug into a Type I wall socket, you need a plug adaptor. The plug adaptor does not change the voltage. It merely allows you to plug your piece of equipment into the wall outlet and that can be a dangerous thing to do.
To avoid the snap, crackle and expletive of 120v gear, being "cooked" by 240v of electricity, you need either a step-down converter or step-down transformer. If you want to power something electronic, you will need a transformer. Transformers are usually more expensive than converters.
When not in use, transformers and converters should be unplugged from the socket to avoid risk of damage to them from unstable current.
If you are not completely confident about what you need and how to use it, I strongly recommend that you check with the shop where you purchased your equipment. They can advise about your specific needs. You may be pleasantly surprised to discover that your gear can operate on both North American 110V and 240v and that all you need is the plug adaptor.
When thinking about the equipment you will use, consider that there is a strict baggage weight limit of 22 pounds on flights within PNG. There will be more information on baggage limits in a future posting.