What is "half time"

Half \Half\ (h[aum]f), a. [AS. healf, half, half; as a noun, half, side, part; akin to OS., OFries., & D. half, G. halb, Sw. half, Dan. halv, Icel. h[=a]lfr, Goth. halbs. Cf. Halve, Behalf.]

1. Consisting of a moiety, or half; as, a half bushel; a half hour; a half dollar; a half view.

   Note: The adjective and noun are often united to form a compound.

2. Consisting of some indefinite portion resembling a half; approximately a half, whether more or less; partial; imperfect; as, a half dream; half knowledge. Assumed from thence a half consent. --Tennyson. Half ape (Zo["o]l.), a lemur. Half back. (Football) See under 2d Back. Half bent, the first notch, for the sear point to enter, in the tumbler of a gunlock; the halfcock notch. Half binding, a style of bookbinding in which only the back and corners are in leather. Half boarder, one who boards in part; specifically, a scholar at a boarding school who takes dinner only. Half-breadth plan (Shipbuilding), a horizontal plan of one half a vessel, divided lengthwise, showing the lines. Half cadence (Mus.), a cadence on the dominant. Half cap, a slight salute with the cap. [Obs.] --Shak. At half cock, the position of the cock of a gun when retained by the first notch. Half hitch, a sailor's knot in a rope; half of a clove hitch. Half hose, short stockings; socks. Half measure, an imperfect or weak line of action. Half note (Mus.), a minim, one half of a semibreve. Half pay, half of the wages or salary; reduced pay; as, an officer on half pay. Half price, half the ordinary price; or a price much reduced. Half round.

   1. (Arch.) A molding of semicircular section.

   2. (Mech.) Having one side flat and the other rounded; -- said of a file.

      Half shift (Mus.), a position of the hand, between the open position and the first shift, in playing on the violin and kindred instruments. See Shift.

      Half step (Mus.), a semitone; the smallest difference of pitch or interval, used in music.

      Half tide, the time or state of the tide equally distant from ebb and flood.

      Half time, half the ordinary time for work or attendance; as, the half-time system.

      Half tint (Fine Arts), a middle or intermediate tint, as in drawing or painting. See Demitint.

      Half truth, a statement only partially true, or which gives only a part of the truth.
      --Mrs. Browning.

      Half year, the space of six months; one term of a school when there are two terms in a year.

alt. 1 (lb en sports) The interval between the two halves of a sports match. 2 The time taken for a physical quantity to halve the difference between its present value and its final value. n. 1 (lb en sports) The interval between the two halves of a sports match. 2 The time taken for a physical quantity to halve the difference between its present value and its final value.

In signal processing, the half time is the time it takes for the amplitude of a pulse to drop from 100% to 50% of its peak value.

Category:Signal processing

Half time may refer to:

• Half-time, an interval between two periods of a sporting match
• Half time (electronics), the time it takes for a pulse to drop to 50% of its peak amplitude
• Half time (physics), the time for a quantity to halve the difference between its present and final values
• Half time (music), a type of feel that alters the meter of music
• "Halftime" (song), a song by Nas

The half time is the time taken by a quantity to reach one half of its final value, where the rate of change is proportional to the difference between the present value and the final value (i.e. in exponential decay processes). It is synonymous with half-life, but used in slightly different contexts.

The diagram shows the increase in the quantity (red) in response to a step-change in the motive force that changes it (blue). The time-axis is in multiples of the half time. It can be seen that the quantity increases to one-half of its final value after one half time, to three-quarters after two half times, to seven-eighths after three half times, and so on.

The relationship between the quantity (Q) and time (t) is described by the mathematical formula:

where Q is the final value and is a constant, approximately equal to 0.69 divided by the half time – more precisely: log(2) / (half time).

Where the quantity decreases in response to a step-decrease in the motive force that changes it, the curve is mirrored in the time-axis and may be referred to as exponential decay.

The concept of half time is used in diving physiology where body tissues take up and release inert gases (usually nitrogen) following changes in depth. Different tissue types have different half times for a given inert gas, and modelling the uptake and release of gases by the tissues is important to avoid decompression sickness.

Half Time was an American Thoroughbred racehorse. He won the 1899 Preakness Stakes.