It has nothing to do with how electricity works and everything to do with the negotiation between the charger, cord and device. They all contain microchips that contains the supported wattage and amperage and they will select the highest supported wattage and amperage by all parts of the chain.
VIKTORVAV99 t1_itmxpl5 wrote
Reply to comment by ChefArtorias in USB-C iPhone will be mandatory in Europe as EU law passes final stage by prehistoric_knight
It has nothing to do with how electricity works and everything to do with the negotiation between the charger, cord and device. They all contain microchips that contains the supported wattage and amperage and they will select the highest supported wattage and amperage by all parts of the chain.