Question

A component used to control current is:

Answer 1

An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is important to control current as excess current leads to excessive generation of heat, and the risk of fire or damage to equipment.

Complete answer:
A sustained overload current results in overheating of conductors and other components and will cause deterioration of insulation, which may eventually result in severe damage and short circuits if not interrupted.
So, it is very important to control the excessive current, the component which is used is the resistor. Resistor is an electrical component that reduces the electric current. The resistor's ability to reduce the current is called resistance. The SI unit of resistance is $\Omega$. The formula for resistance is given by the expression $R = \dfrac{V}{I}$.
Resistance has various applications in day to day life also. Some of them are that resistors are used in a heater, toaster, microwave, electric stove, and many more heating appliances. In a light bulb, the metal filament glows white-hot due to the very high temperature produced from the resistance when electricity is passed through it.

Additional Information:
Resistors can be connected in two combinations, namely, series combination and parallel combination. In a series circuit, the output current of the first resistor flows into the input of the second resistor; therefore, the current is the same in each resistor. In a parallel circuit, all of the resistor leads on one side of the resistors are connected together and all the leads on the other side are connected together.

Note:
Although resistance is used to control the current but when over-current flows through the housing appliances, then a fuse is used. Fuses are sacrificial devices used to protect much more expensive electrical components from the damaging effects of over-current.