A coil is a generic name for an electrode in the shape of a spiral. Among the different types of coils, there are coils called “inductors” which are used for electrical applications. Inductors can be further categorized into RF inductors used for signal processing, and power inductors for power supply lines. The power inductors discussed in this section form part of the voltage conversion circuit in a DC-DC converter or other device.
Here we will explain the operation of a power inductor in a DC-DC converter. A power inductor is used in a step-up, step-down, or step-up/step-down circuit to convert a certain voltage to the required voltage. Among those different circuits, it is primarily used in a type of circuit called a “switching regulator.”
Figure 1-1 shows an example of a switching regulator step-down circuit.
It uses an IC, power inductor, and capacitor to convert a DC input voltage to the required output voltage. The power inductor works with the capacitor to play the role of rectifying the rectangular wave output from the IC to a direct current.
If either one of these components is missing, the output cannot be properly rectified.
What is a transformer?
A transformer is a device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage.
Where are transformers used?
Transformers are employed for widely varying purposes. For example, a transformer is often used to reduce the voltage of conventional power circuits to operate low-voltage devices and to raise the voltage from electric generators so that electric power can be transmitted over long distances.
Why is the iron core of a transformer laminated?
The iron core of a transformer is laminated to reduce eddy currents. Eddy currents are the small currents that result from the changing magnetic field created by the alternating current in the first coil. They need to be minimized so they won’t disturb the flow of electricity from the primary coil to the secondary coil.
transformer, device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage. Transformers are employed for widely varying purposes; e.g., to reduce the voltage of conventional power circuits to operate low-voltage devices, such as doorbells and toy electric trains, and to raise the voltage from electric generators so that electric power can be transmitted over long distances.