# Evaluating the probability of damage to a laptop computer from power surges

Power cords for laptop computers have a transformer built into them. The power supply has a transformer that steps down mains level power to a lower voltage and rectifier that converts the current from AC at the mains to DC.

Power surges con occur for a variety of reasons, such as a nearby lightning strike. If a damaging power surge were to occur, would the power supply prevent the power surge from damaging the laptop computer?

An occupational hazard of mine is working with a lot of people who own laptop computers. I also happen to live in the central plains of the United States, and we get our fair share of thunderstorms. They're not as pretty as the lightning storms of Phoenix, AZ, but they're generally a lot more powerful.

Anecdotally, I've heard of multiple times where the power supply (aka "the brick") for the laptop computer becomes a sacrificial component and will be destroyed by a power surge whereas the laptop itself is just fine.

I have heard of similar stories with desktop computers, but on a much more rare basis. Generally, damaging surges will take out the power supply and the mainboard with a desktop.

Laptop computers have an additional block of circuitry that directs power to the battery for charging purposes and / or directing power to the rest of the laptop circuitry. I would hazard a guess that this additional charging circuitry provides an additional measure of shunting and helps protect laptop computers from damaging power surges.

Between laptops and desktops, I have probably heard of an equal number of instances of laptop power supplies and desktops being destroyed. I have heard of the actual laptop being destroyed less frequently.

Your most likely risk is losing the laptop power supply due to the damaging power surge. I'm not certain how to evaluate that overall risk as almost everyone I know connects their electronics through protective power strips.

But you're not completely risk-free of the laptop being damaged. Damaging power surges are notoriously fickle and can have incredible variance in intensity. Lightning strikes vary in intensity; the distance between the strike and the equipment will vary; and the number of connected circuits between the strike and your equipment will also vary.

From a protective standpoint, one of the best things you can do is put a surge protector block within the circuit panel supplying mains power to your dwelling. From there, make sure that any sensitive electronics are powered through surge protecting power strips. Those two measures will provide you a significant reduction of risk at a modest price. And if you're really concerned, power everything down and disconnect the power strip when a storm is rolling through.