Copper coils are usually used in inductors. In the inductive coil. When an inductor is accumulating energy, it tends to limit the number of wires flowing through it. When an inductive coil accumulates enough energy to produce a strong enough magnetic field, the current is allowed to pass completely. Inductance tends to resist any change in energy flow. The coil is designed to help generate a magnetic field. Inductive coils do not actively seek energy. It is considered passive because the current must come from another source. Although inductive coils receive, accumulate and regulate energy, they will remain dormant if they do not receive any current. Inductors are used in all types of electrical equipment, including computers, radios, and mobile devices. Most inductors that handle high-frequency currents contain ferrite cores. The magnetic core is made of a magnetic material, such as iron oxide. Copper wire is usually wrapped around an iron core. Some inductors have bare wires, while others do not have a lower energy frequency. They usually have a better response to inductors containing some kind of laminated core. Steel is used to make a center. Steel is usually insulated to prevent energy leakage. The inductance coil does not work alone. They are part of the power system and are used to regulate the energy flow from the power supply. The power supply can be a battery or a power socket. There is usually some type of circuit or circuit board connection to pass the current of the power supply through the coil. In most designs, current flows through the inductor, but in several directions. It has the ability to send current from both sides to objects that need power, such as bulbs, computer monitors or stereos. One side of the inductor will receive the current from the power supply and send the current to the switch. In most electrical system designs, the power supply can be adjusted by the switch.