| A | B |
|---|
| insulator | electrons flow poorly through them. |
| conductor | electrons flow well through them. |
| current | flow of charges that is created when electrons move. |
| resistance | opposition to the movement of electrons. |
| voltage | electrical force, or pressure, that occurs when electrons and protons are separated |
| AC | alternating current. It reverses polarity. Power that comes to your house from the power lines. |
| DC | direct current. Always flows in the same direction. Battery power |
| Analog | signal patterns that fluctuate, evolve, or continually change |
| Digital | signal patterns that remain constant. 0s and 1s. |
| Safety Ground | 0 volts. |
| Propagation | travel. |
| Attenuation | loss of signal strenght over distance. |
| Impedance | total opposition to current flow. |
| EMi/RFi | external sources of electrical impulses that can affect signal over the wire. Electromagnetic interferance and radio frequency interference. |
| Crosstalk | electrical noise that comes from other wires in the same cable. |
| Latency | delay |
| Collision | two bits from different computers are on the same medium at the same time. |
| Encoding | convert binary data into a form that can travel through a physical communication link. |
| Jitter | bits can arrive earlier or later than expected |
| Reflection | when energy for the bits bounces back in the media |
| Noise | unwanted signals added to electromagnetic or optical signals |
| Dispersion | signal broadens in time. |
