Capacitance in Physics

A capacitor holds charge by keeping two conductors close enough that they attract each other across the gap, and its capacitance measures how much charge it takes to raise the voltage by one volt. That ratio is fixed by geometry alone, which is why a capacitor stores the same amount for the same voltage no matter what circuit it sits in. Slipping an insulator between the plates makes the storage cheaper, because the material's molecules stretch and cancel part of the field. The blocks give the definition, the shapes worth remembering, the two ways of joining capacitors, the energy a charged one holds, and the dipole relations that explain from first principles why a dielectric helps at all.