Okay kiddo, do you know what power is? It's like the energy that helps make things work.
Now, sometimes we don't need a lot of power to make something work. For example, if we want to turn on a small light, we only need a little bit of power. That's what we call 'small power' - it's when we only need a small amount of energy to operate something.
Small power is can be used for lots of things! For example, if we want to charge our phone, we only need a small amount of power from a charger. Or if we want to run a small fan to keep us cool, we only need a little bit of power from the batteries.
So basically, small power is just enough energy to get the job done without wasting any extra energy that we don't need. It's like using just the right amount of force to open a door - you don't need to push it really hard if you can just gently nudge it open.