What Is Radio Frequency Induction? Part 1
This topic poses the question of how a Radio Frequency (RF) field can induce a voltage or current in some system or device.
Firstly let's discuss a Field. A Field is an influence of some sort. It is a presence of some kind of energy. A crude analogy is to think of the blowing of the wind. It is force in the environment that moving, causing an influence upon what it encounters.
A better analogy is that of light from an ordinary light bulb. The light radiates out and impinges upon various objects. The light may or may not interact with the objects that it encounters. If you hold your hand near a light bulb and feel heat, then the light energy is interacting with your hand. It is depositing energy into your hand and you feel this as heat. Aside: have you ever felt your ear or your head get hot from holding a cell phone near to it? Have you ever wondered if the cell phone radiation posed a health or safety concern? There are various other accesories that can have the same effect, including blue tooth cell phone accessory.
In the area of Physics known as Electricity and Magnetism, we speak of two types of fields: Electric fields and Magnetic fields. Let's focus on the Magnetic fields and understand Induction from that perspective.
You are probably familiar with a bar magnet. It has a magnetic Field associated with it and this bar magnet will readily attract-to and stick-to various magnetic materials, like iron.
We are getting closer to induction. Now, conceptually, take some ordinary copper wire and form it into a coil of wire, perhaps with a total of 100 turns of wire. Connect the ends of the wire to a small light bulb, like that which might be used in a small flashlight. Now we wave the bar magnet, quickly, in the immediate vicinity of the coil of wire and we find that the light bulb flashes briefly when wave it past the coil. NOTE: we may have to turn off the lights in the room to see the bulb flashing if the magnet is not too strong.
What is happening? Answer: Induction. The changing magnetic field is inducing a current (a flow of electrons) in the coil of wire. That current is flowing through the light bulb, and we see it flash. In another article we will see that induction is happening all around us all of the time. RF Induction is the Induction that occurs from RF energy. RF energy such as that in a cell phone.