A price asked, an electrical quantity, and a duty entrusted. All three are something laid on.
Old French chargier, from Medieval Latin carricare (to load a cart), from Latin carrus (a wagon) — the same root as 'carry'; a charge is, at the root, a load placed on someone.
A price asked, an electrical quantity, or a duty entrusted — three things that are, at the root, one thing laid onto another.