vertical resolution The number of scanning lines presented by a video display from the top of the image to the bottom; the number of scanning lines in a video signal. NTSC video has a vertical resolution of 480 lines; HDTV has a vertical resolution of 720 or 1080 lines.

video display A device that converts a video signal into a visual image.

video monitor A video display with video input and output jacks but no television tuner.

video upconverter Device or circuit within a device that converts a lower-resolution video signal to a high-resolution video signal.

voice coil Coil of wire inside a loudspeaker driver through which current from the power amplifier flows.

volt Unit of electromotive force. One volt is defined as the difference in potential required to make one ampere of current flow through one ohm of resistance; see also “voltage.”

voltage Analogous to electrical pressure. Voltage exists between two points when one point has an excess of electrons in relation to the other point. A battery is a good example: the negative terminal has an excess of electrons in relation to the positive terminal. If you connect a piece of wire between a battery’s positive and negative terminals, voltage pushes current through the wire. Current flow is the electron charge in motion through the conductor. One volt across 1 ohm of resistance produces a current of 1 ampere.