Everywhere we look in life, we find some form of resistance. For airplanes, it shows up in the form of wind (and maybe an occasional bird or two). Water keeps kayakers afloat, but it also slows them down some. Even the indomitable James Bond in his Aston Martin DB5 had to contend with resistance when his tires hit the road. It would be great if all the electrons in a current could go gliding across a copper wire (or another conductor) free and clear, but pesky resistance prevents them from doing so.
Resistance in a conductor opposes the flow of an electric current. This results in some of the electrical energy changing to heat, which you want to minimize. Hot wires can be dangerous wires. On the other hand, resistance is built into the system to control the strength of the current running through it. You also don’t want your blender getting hit with 50 amps of electricity when you’re mixing a fruit shake. Electrically speaking, resistance is measured in ohms.
Ohm’s Law (Ohm was a German physicist with a great name) basically says that the smaller the wire or conductor, the greater the resistance to a current. If you crank up the amps, you get even more resistance, sometimes to the point of overheating and causing a fire. Loads that require more amps also require larger wire to handle the current flow. If you increase the size of the wire, the resistance goes down, and you get a weaker current with less voltage drop. This is one of the reasons you have several different sizes of wire in your house.
Think of it this way: Imagine that the fire department is putting out a fire in your house.
You’re happy that they’re using a big hose (just as a No.6 or No.10 is a big wire for big jobs). But what if you’re just watering your garden? Then you want to conserve water and avoid flooding the garden. You’ll use a small hose (just as a No.12 or No.14 wire is good for small items such as light fixtures).
Resistance in a conductor opposes the flow of an electric current. This results in some of the electrical energy changing to heat, which you want to minimize. Hot wires can be dangerous wires. On the other hand, resistance is built into the system to control the strength of the current running through it. You also don’t want your blender getting hit with 50 amps of electricity when you’re mixing a fruit shake. Electrically speaking, resistance is measured in ohms.
Ohm’s Law (Ohm was a German physicist with a great name) basically says that the smaller the wire or conductor, the greater the resistance to a current. If you crank up the amps, you get even more resistance, sometimes to the point of overheating and causing a fire. Loads that require more amps also require larger wire to handle the current flow. If you increase the size of the wire, the resistance goes down, and you get a weaker current with less voltage drop. This is one of the reasons you have several different sizes of wire in your house.
Think of it this way: Imagine that the fire department is putting out a fire in your house.
You’re happy that they’re using a big hose (just as a No.6 or No.10 is a big wire for big jobs). But what if you’re just watering your garden? Then you want to conserve water and avoid flooding the garden. You’ll use a small hose (just as a No.12 or No.14 wire is good for small items such as light fixtures).
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