Final answer:
A rheostat is a device that adjusts current flow in a circuit by regulating resistance, unlike an ammeter which only measures current but does not control it.
Step-by-step explanation:
A device that indicates the amount of current flowing through equipment and regulates the amount with a dial or knob is known as a rheostat. The rheostat can adjust the resistance in a circuit, thereby controlling the current flow as per Ohm's law, which states that the current in a circuit is directly proportional to the voltage and inversely proportional to the resistance. Note that most electrical appliances are rated in amperes (or amps) required for proper operation, as are fuses and circuit breakers. A load refers to a component or portion of a circuit that consumes electric power, a fuse is a safety device that interrupts the flow of current when it exceeds a certain threshold, and a circuit is a path through which electricity flows. However, an ammeter is used to measure current flow but does not regulate it.