A device in electricity that is analogous to a restriction in a water pipe is:

What would a restriction in a water pipe do? - if it lowers the amount of water flowing it would be comparable to a electrical resistance, which lowers the amount of charge flowing. - if it introduces more water into the pipe it would be comparable to a electrical generator. - if it allows water to flow freely without restriction it would be the same as an electrical conductor if it just measures the amount of water flowing it would be the same as an ammeter

Water pipe controls flow of water

Resistance (resistor) controls flow of electrons