impedance

Impedance is a bit like resistance, but it's a bit more complicated than that. Think of it like a wall. Resistance is like a wall that won't let anything pass through it, but impedance is like a wall that will let some things pass through, but not all of them. When you plug something into the wall, like a headphone or a speaker, some of the sound waves can get through, but other types of sound waves can't pass through the wall at all. Impedance is kind of like that, but instead of sound, it's electricity that's trying to get through. Things like speakers and headphones have a certain amount of impedance, and when you connect them to an amplifier, the amplifier has to use more power to push the electricity through the wall (or the impedance).