Use of inductor in the Modern Technology

Inductors are used extensively with capacitors and resistors to create filters for analog circuits and in signal processing. Alone, an inductor functions as a low-pass filter, since the impedance of an inductor increases as the frequency of a signal increases. When combined with a capacitor, whose impedance decreases as the frequency of a signal increase, a notched filter can be made that only allows a certain 

frequency range to pass through. By combining capacitors, inductors, and resistors in a number of ways advanced filter topologies can be created for any number of applications. Filters are used in most electronics, although capacitors are often used rather than inductors when possible since they are smaller and cheaper.

Sensors:

Contactless sensors are prized for their reliability and ease of operation and inductors can be used to sense magnetic fields or the presence of magnetically permeable material from a distance. Inductive sensors are used at nearly every intersection with a traffic light to detect the amount of traffic and adjust the signal accordingly. These sensors work exceptionally well for cars and trucks, but some motorcycles and other vehicles do not have enough of a signature to be detected by the sensors without a little extra boost by adding a h3 magnet to the bottom of the vehicle. Inductive sensors are limited in two major ways, either the object to be sensed must be magnetic and induce a current in the sensor or the sensor must be powered to detect the presence of materials that interact with a magnetic field. This limits the applications of inductive sensors and has a major impact on designs that use them.

Transformers:

Combining inductors that have a shared magnetic path will form a transformer. The transformer is a fundamental component of national electrical grids and found in many power supplies as well to increase or decrease voltages to a desired level. Since magnetic fields are created by a change in current, the faster the current changes (increase in frequency) the more effective a transformer operates. Of course, as the frequency of the input increases, the impedance of the inductor begins to limit the effectiveness of a transformer. Practically inductance based transformers are limited to the 10s of kHz, usually lower. The benefit of ahigher operating frequency is a smaller and lighter weight transformer can be used to deliver the same load.

Energy Storage:

Like capacitors, inductors can be used for energy storage. Unlike capacitors, inductors have a severe limitation on how long they can store energy since the energy is stored in a magnetic field which collapses quickly once power is removed. The main use for inductors as energy storage is in switch-mode power supplies, like the power supply in a PC. In the simpler, non-isolated switch-mode power supplies, a single inductor is used in place of transformer and energy storage component. In these circuits, the ratio of the time the inductor is powered to the time it is unpowered determines the input to output voltage ratio.