What’s up with all the different talk about volts, watts, and amps in Docking Drawers specifications? To help make it easier to understand why Charging Outlets are limited to 3amps and Powering Outlets are rated for 20amps, etc. Docking Drawer wrote up a quick and easy tutorial that will help you to understand it all!
Let's start with watts, a measurement of power. Now power is really where the rubber meets the road. If you have thick, long hair and you want to dry it quickly, you are going to need a blow dryer with a lot of power. Likewise when you want to defrost a 4-quart container of frozen soup in 10 minutes, you need a microwave with a lot of power.
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Power is measured in a unit called watts. A professional salon quality blow dryer might be rated at 1200 watts, whereas the wimpy ones you may find in a hotel might only be 600 watts. The higher the wattage, the higher the power.
Now that you understand the definition of power, the rest is quite simple! Here is the formula we engineers use: volts x amps = watts
In other words, you'll need a combination of volts and amps to get the desired watts (power). If you have very high voltage, you can get away with low amperage to yield the desired number of watts. On the other hand, if you have low voltage then you need high amperage to get the same power. Here are some examples:
120V x 10A = 1200 watts
240V x 5A = 1200 watts
Houses typically have two different voltages: 120v and 240v.
Why are there two different voltages? Why not just use one?
This is due to an important property related to current. Current, just so we're clear, is the flow of electricity in a conductor such as a wire. Current is measured in amps. Think of current as a river. You can only get so much water down a river before the river floods its banks. Current is the same way. If you pass too much current through an electrical wire, the wire will get hot. Eventually that wire will get so hot it will melt and possibly catch surrounding areas on fire. That is why all electric circuits use circuit breakers. A circuit breaker is similar to dams on a river that prevent excessive water (current) from causing flooding. The only way to pass high current through a wire is to make the wire really thick. Unfortunately, this is not only impractical but also quite expensive. Luckily there is a trick! By simply increasing the voltage, it’s possible to deliver the same power (watts) while using less current (amps). This allows smaller, less expensive wiring.
This is why houses have two different voltages. Appliances such as ovens and electric clothes dryers are very high power (they are high wattage devices). If you ran your 5000 watt electric range at 120V then you would need about 42A of current and a wire about the diameter of a pencil to safely carry the current without getting too hot. On the other hand, if we increased the voltage to 240V, then the required current is now only 21A and the wire can be much smaller (and cheaper).
Cool fact: The power transmission wires that bring electricity from the power plants to thousands of homes are running at HUNDREDS OF THOUSANDS OF VOLTS! This is so that the current is relatively low and the wire is relatively small in diameter even though those wires are delivering millions of watts of power. If those wires were at 240V, they would have to be many feet thick in diameter which is obviously impractical, not to mention costly.
Hopefully this help you to understand the relationship between volts, amps, and watts. For more information about their relationship, visit this great site. If you have questions, don't hesitate to contact us!
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