Voltage

Voltage is not something that flows: it is a difference, like a slope. Between a plate charged minus and a plate charged plus lies an electric field: a charge released there is pushed, like a ball released on a slope. The bigger the difference, the steeper the slope, the faster the charge accelerates. The volt measures that steepness: how much energy each charge gains going down from one point to the other. A phone battery is a gentle slope of about 3.6 V1; a wall socket, a steeper one; a lightning bolt, a cliff. A very steep slope with almost nothing rolling down is not dangerous; it is the amount that comes down, the current, that does the work and the damage. Flip the test charge: it climbs the slope, and that is exactly what charging a battery does.