| RESISTANCE: |
in dc circuit, the opposition a material offers to current flow, measured in ohms (Ω). In ac circuit, resistance is the real component of impedance, and may be highter than the value measured at dc. |
| IMPEDANCE: |
the total opposition a circuit, cable or component offers to alternating current flow. It includes both resistance and reactance and is generally expressed in ohms (Ω) and designated by the symbol Z. |
| CAPACITANCE: |
the ability of a dielectric material between conductors to store electricity when a difference of potential exist between the conductors. The unit of measurement is the Farad, which is the capacitance value that will store the charge of one Coulomb when a one-Volt potential difference exists between the conductors. In ac, the Farad is the capacitance value which will permit one Ampere of current when the voltage across the capacitor changes at a rate of one Volt per second. |
| INDUCTANCE: |
a property of a conductor or circuit which resist a change in current. It causes to lag behind voltage changes and is measured in Henrys. |
| ATTENUATION: |
the decrease in magnitude of a signal as it travels throught any trasmitting medium, such as a cable or circuit. Attenuation is measured as a ratio or as the logarithm of a ratio (decibel). |
| VELOCITY OF PROPAGATION: |
the trasmission speed of electrical energy in a lenght of cable compared to speed in free space. Usually expressed as a percentage. |