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Information about Gain

In electronics, gain is a measure of the ability of a circuit to increase the power or amplitude of a signal. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined as the decimal logarithm of the same ratio.

Thus, the term gain on its own is ambiguous. For example, 'a gain of five' may imply that either the voltage or the power is increased by a factor of five.

In laser physics, gain may refer to the increment of power along the beam propagation, and its dimension is m-1 (inverse meter) or 1/meter.

Logarithmic units and decibels

Power gain, in decibels (dB), is defined as follows:
where Pin and Pout are the input and output powers respectively.

A similar calculation can be done using a natural logarithm instead of a decimal logarithm. The result is then in nepers instead of decibels.

When gain is calculated using voltage instead of power, making the substitution (P=V2/R), the formula is:



In many cases, the input and output impedances are equal, so the above equation can be simplified to:



and then:



This simplified formula is only valid to calculate a gain in decibels if the impedances at input and output are equal.

Example

Q. An amplifier has an input impedance of 50 ohms and drives a load of 50 ohms. When its input () is 1 volt, its output () is 10 volts. What are its voltage gain and power gain?

A. Voltage gain is simply:
The units V/V are optional, but make it clear that this figure is a voltage gain and not a power gain. Using the expression for power, P = V2/R, the power gain is:
Again, the units W/W are optional. Power gain is more usually expressed in decibels, thus:


A gain of factor 1 (equivalent to 0 dB) where both input and output are at the same voltage level and impedance is also known as unity gain.

See also

This article contains material from the Federal Standard 1037C, which, as a work of the United States Government, is in the public domain.
Electronics is the study of the flow of charge through various materials and devices such as, semiconductors, resistors, inductors, capacitors, nano-structures, and vacuum tubes. All applications of electronics involve the transmission of power and possibly information.
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Circuit may mean:
  • Circuit (Band)
  • Circuit (airfield)
  • Circuit court
  • Circuit (film)
  • Circuit (film character)
  • Circuit (LCMS), local grouping of congregations in the Lutheran Church - Missouri Synod
  • Circuit party, a gay dance event

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In physics, power (symbol: P) is the rate at which work is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time.
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amplitude is a nonnegative scalar measure of a wave's magnitude of oscillation, that is, the magnitude of the maximum disturbance in the medium during one wave cycle.

Sometimes this distance is called the peak amplitude
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Signal, signals, signaling, or signalling may refer to:

Scientific concepts
  • Signal (electrical engineering), a varying quantity that can carry information.

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This article or section is in need of attention from an expert on the subject.
Please help recruit one or [ improve this article] yourself. See the talk page for details.
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In telecommunication, signalling (UK spelling) or signaling (US spelling) has the following meanings:
  • The use of signals for controlling communications.

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In telecommunication, signalling (UK spelling) or signaling (US spelling) has the following meanings:
  • The use of signals for controlling communications.

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logarithm (to base b) of a number x is the exponent y that satisfies x = by. It is written logb(x) or, if the base is implicit, as log(x).
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Ambiguity is the property of words, terms, notations and concepts (within a particular context) as being undefined, undefinable, or without an obvious definition and thus having an unclear meaning.
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Voltage (sometimes also called electric potential difference or electrical tension) is the potential similarity of electrical potential between two points of an electrical or electronic circuit, expressed in volts.
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For delivered electrical power, see .
Electric power is defined as the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt.

When electric current flows in a circuit with resistance, it does work.
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Laser Physics is international scientific journal, published by MAIK NAUKA/INTERPERIODICA PUBLISHING , and distributed through [1] publishing company.

topics of the journal

The journal specializes in the laser science, but also publishes papers about

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The power gain of an electrical network is the ratio of output power to input power. Unlike other signal gains, such as voltage and current gain, power gain is ambiguous as the terms "input power" and "output power" are not strictly defined.
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The decibel (dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power) relative to a specified or implied reference level.
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The natural logarithm, formerly known as the hyperbolic logarithm, is the logarithm to the base e, where e is an irrational constant approximately equal to 2.718281828459.
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neper (Symbol: Np) is a unit of ratio. It is not an SI unit but is accepted for use alongside the SI. It is used to express ratios, such as gain and loss, and relative values. The name is derived from John Napier, the inventor of logarithms.
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Joule's laws are a pair of laws concerning the heat produced by a current and the energy dependence of an ideal gas to that of pressure, volume, and temperature, respectively.
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Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal alternating current (AC). Electrical impedance extends the concept of resistance to AC circuits, describing not only the relative magnitudes of the voltage and current, but also the
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This article is about the number one. For the year AD 1, see 1. For other uses, see 1 (disambiguation).

0 1 2 3 4 5 6 7 8 9 →

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In radio transmission, transmitter power output (TPO) is the actual amount of power (in watts) of radio frequency (RF) energy that a transmitter produces at its output.
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The absolute gain of an antenna, for a given direction and polarization, is the ratio of (a) the power that would be required at the input of an ideal isotropic radiator to (b) the power actually supplied to the given antenna, to produce the same radiant intensity in the far-field
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In telecommunication, the term loop gain has the following meanings:

1. The total usable power gain of a carrier terminal or two-wire repeater.

Note: The maximum usable gain is determined by, and may not exceed, the losses in the closed path.
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In telecommunication, insertion gain is the gain resulting from the insertion of a device in a transmission line, expressed as the ratio of the signal power delivered to that part of the line following the device to the signal power delivered to that same part before insertion.
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The power gain of an electrical network is the ratio of output power to input power. Unlike other signal gains, such as voltage and current gain, power gain is ambiguous as the terms "input power" and "output power" are not strictly defined.
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In telecommunications, the term directive gain has the following meanings:

1. Of an antenna, the ratio of 4π times the radiant intensity in a given direction (i.e., power radiated per unit solid angle), to the total power.
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In telecommunicationS, net gain is the overall gain of a transmission circuit.

Note 1: Net gain is measured by applying a test signal at an appropriate power level (see Note 5)
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In a spread spectrum system, the process gain (or 'processing gain') is the ratio of the spread bandwidth to the unspread bandwidth. It is usually expressed in decibels (dB).
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In a spread spectrum system, the process gain (or 'processing gain') is the ratio of the spread bandwidth to the unspread bandwidth. It is usually expressed in decibels (dB).
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Automatic gain control (AGC) is an adaptive system found in many electronic devices. The average output signal level is fed back to adjust the gain to an appropriate level for a range of input signal levels.
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