# Eli5: What is a watt?

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I want to go camping but use a generator to run a computer. A laptop and desktop need different watts. You have to put the right amount of watts into each device. Different outlets have different watts. The watts in a cigarette lighter are different than the watts in a generator.

What is a watt? What do different watt numbers mean? What happens if I have a device sending too many watts or not enough to a device? Is it critical or just ideal to match them?

In: Engineering

“Watts” are a measure of power. A device that needs more power demands a higher wattage.

A generator’s wattage will be an upper limit – it cannot supply any more than this number but less is fine.

If you ask for too much wattage, then either the device or the generator won’t work right. Best case scenario, a light is dim or it makes an odd noise. Worst case scenario is the generator stalls, although much more likely it would blow a fuse.

Watt is a measurement of energy over time. Devices will “pull” as much wattage as they need, up to the generator’s limit.

It’s the SI unit for power, which is the rate of energy transfer. One watt is equivalent to one joule per second. For electrical devices, the power is also equivalent to the voltage multiplied by the current.

> You have to put the right amount of watts into each device.

You have to put the right amount of *volts* into each device (though some devices can cope with a large range of voltages, and some power supplies can switch to some different voltages depending on what the device needs). The current, and therefore the power, drawn by the device will typically fluctuate. Any transformer/power socket/power supply will have a maximum rated current, and if you go above that, then hopefully there is a fuse or circuit breaker that will cut the power to the device, otherwise bad things can start happening.

Watts is work getting done. It’s the electricity doing something. Volts and amps is electricity in a circuit but only running through a circuit and not doing anything useful. If that electricity makes a motor move, a light come on, heat being emitted, etc, that’s watts.

One watt is one volt times one amp. A volt is potential energy and an amp is kinetic energy. If one volt pushes one amp through something to do work, it generates one watt. If you need more than one watt you need to increase voltage or amps.

Current (Amps) times Voltage (Volts) = Watts.

For example: 3 Amps current at 110 Volts = 330 Watts.

Be cautious running a computer off a generator..