Time out for terms!
Inductive reactance is the proper term for opposition to current flow through a coil. Resistance of a circuit and inductive reactance, both measured in Ohms, makes up impedance. The other confusing term in radio is AC.
In many radio discussions AC does not mean the alternating current that powers your appliances, rather, it means the way audio signals alternate in a wave like fashion. Huh? As we've just seen above and on the on the previous page , we need a change in current flow through a coil to get radiation. Current must go on and off to release the electromagnetic energy stored within the coil.
AC in radio means the natural alternating current of a voice signal, that is, the normal up and down waveform of the analog signal. In this case the rise and fall of a signal above a median point, that is, the top and bottom of a wave. Alternating current. Get it? A battery powered walkie talkie illustrates the difference between AC signaling current and AC power current.
A battery powered radio transmitter uses direct current to do all things. Including converting your voice, through the microphone, into a signal it can transmit. But the signal it transmits is not called a DC signal but an AC signal. That's because the radio rapidly oscillates (or alternates) the original signal. This is the needed step to get the signal high enough in the frequency band so that it will radiate from the antenna. AC, in this case, is not the power coming out of a wall outlet, it is the alternating current formed by waves of acoustical energy in the voice band converted into electrical waves by the radio circuitry. These terms get clearer as you read more. But if you are really mystified, read this little tutorial on how basic radio circuits work. I think it will help you a great deal and you can always come back here to continue.
