Why Are Laptop Adapters Heavy?

A laptop -- before it gains the extra weight of power adapter hardware.

Laptops are forever getting smaller and lighter, so why are their power adapters so heavy? That 5-pound laptop appealed at first, but no one mentioned the adapter would weigh as much again.

Types of Adapter

A transformer is a block of iron wrapped in wire.

The weight of an adapter depends on the technology used to reduce household power down to the level needed by your device. Common adapters use a "transformer" to do this. A popular but older and heavier type of adapter uses a large transformer -- these are often called "linear" power supplies or just "transformers."

Smaller and lighter adapters have become more popular over recent years and use a much smaller version of the transformer. This type is called a "switched mode" power supply.

Output Rating

A netbook power supply is likely to be very light.

No matter which technology is used, adapters can't escape the need for a transformer of some kind. This requirements translates to more weight for devices that need more power.

Losing Weight

Universal adapters come with a range of jacks.

Some manufacturers offer an alternative adapter unit. If this is not possible, try a computer or electronics store for a universal laptop power supply. Universal power supplies are often less expensive than an "official" laptop vendor alternative and should be perfectly safe to use, but check the output voltage first -- make sure it matches the figure required by your hardware. If you do go this route, be aware that laptop vendors discourage the use of any unofficial hardware and will probably not honor any warranty, so check first.

References

• XP Power: Power Supply Guide
• NexTag: Universal Power Supply Prices