Forms an inductor. This can be used in tuned circuits, filters or where you want the current to be out of phase with the voltage.
Apart from it's use in electronics, which is a very complicated subject, a coil does indeed produce a magnetic field.
This magnetic field can be used to attract ferrous metals, just like a magnet. The best part is, unlike a magnet, you can switch it on and off.
One application of a magnetic field like this, is a relay. these are just a coil, which attracts a piece of iron, which operates heavy duty switch contacts. So, by operating a tiny switch, or pressing a button, the tiny current to control the relay is being used to switch much larger currents.
This is what happens when you start a car. the ignition switch, via a relay switches hundreds of amps through the starter motor.
Other examples are found in electric motors, generators etc.
It puts the ding and dong in a door chime for example. When the circuit is made an electro magnet moves a core to strike a chime and a spring throws it back against another chime when the circuit is broken. Hence ding and dong.
[1] Use as a choke to block RF from passing through power supply line.
[2] Use on LC tuning circuit.
[3] Use on oscillation circuit.
[4] Use on coupling circuit like IF and RF transformer.
[5] Use on filter circuit.
It is an inductor. The impedance of an inductor goes up linearly with frequency. It does not create an EM field; it only creates a magnetic field.
i know it generates an electrical magnetic field by coiling it; but what is the point of this EM field?
