Ham radio exam preparation: Inductors and Transformers

An inductor is simply a coil or loop of wire which opposes a change in the current within it. Inductance of a coil is measured in Henry. Inductance of a coil will depend on the number of turns in the coil, permeability of the medium inside the coil, cross section of the core, and the spacing between the turns of the coil. The more number of turns there are in the coil, higher the inductance. Higher permeability of the core also increases inductance. Coils with larger cross section have higher inductance. In the case of spacing between the turns of the coil, it is the other way round. Smaller the spacing between the turns of the coil, higher the inductance. The inductance in this discussion is actually self inductance of the coil. A change in the current in the coil induces a voltage within it. One Henry is the amount of inductance required for generating one Volt of induced voltage in the coil when the current is changing at the rate of one ampere per second. As in case of capacitance, smaller units are millihenry and microhenry. Read More: johnsonfrancis...