Inductors and transformers
An inductor is an electromagnet-a coil of wire, with or wire a magnetic core, that produces magnetism when current flows this it. The magnetism forms a store of energy that takes time to fill or element into electronics. They oppose high-frequency currents, preventing mains voltage disturbances getting into circuits or rad signals getting out. With capacitors, they form electrical resonator can filter out unwanted signals (pp. 34-35). Modern eletronic technology uses inductors sparingly because they are impossible include in integrated circuits (pp. 52-53). A transformer is two or coils sharing the same core. It is widely used to step voltages up on down. Changing current through one coil causes magnetic change that affect all the coils, inducing the same voltage in each turn of with. Coils with more turns produce more voltage but less current.