In electronics, **gain** is usually taken as the mean ratio of the signal output of a system to the signal input of the system. A gain of five would imply that either the voltage or power is increased by a factor of five. It has wide application in amplifiers. The field of electronics is the study and use of systems that operate by controlling the flow of electrons (or other charge carriers) in devices such as thermionic valves and semiconductors. ...
In number and more generally in algebra, a ratio is the linear relationship between two quantities of the same unit. ...
In telecommunication, signalling (or signaling) has the following meanings: The use of signals for controlling communications. ...
In telecommunication, signalling (or signaling) has the following meanings: The use of signals for controlling communications. ...
International danger high voltage symbol. ...
Electric power is the amount of work done by an electric current in a unit time. ...
The term amplifier as used in this article can mean either a circuit (or stage) using a single active device or a complete system such as a packaged audio hi-fi amplifier. ...
## Logarithmic units and decibels
In electronics, it is common to use logarithmic units to measure gain. Originally, the bel was used: Logarithmic units are generic mathematical units in which we can express any quantities (physical or mathematical) that are defined as being proportional to values of a logarithm function. ...
- Gain = log
_{10}(*P*_{2}/*P*_{1}) bel where P1 and P2 are the input and output *powers* respectively. This unit is generally too large, so the decibel (one tenth of a bel) became popular in its place. As there are ten decibels (**dB**) in a bel: The decibel (dB) is a measure of the ratio between two quantities, and is used in a wide variety of measurements in acoustics, physics and electronics. ...
- Gain = 10 * log
_{10}(*P*_{2}/*P*_{1}) dB (A similar unit using natural logarithms is called the neper.) The natural logarithm is the logarithm to the base e, where e is equal to 2. ...
For Neper as a mythological god, see Neper (mythology). ...
When gain is calculated using voltage instead of power, making the substitution (*P*=*V*^{2}/*R*), the formula is: Joules law (also known as Joule effect) is a physical law expressing the relationship between the heat generated by the current flowing through a conductor. ...
- Gain = 10 * log ((
*V*_{2}^{2}/*R*) /(*V*_{1}^{2}/*R*) ) dB - Gain = 10 * log ((
*V*_{2}/*V*_{1})^{2} ) dB - Gain = 20 * log (
*V*_{2}/*V*_{1}) dB This formula only holds true if the load impedances are identical. In many modern electronic devices, output impedances are low enough and input impedances high enough that load can be ignored without significantly affecting the calculation. In electrical engineering, Impedance is a measure of opposition to a sinusoidal electric current. ...
The output impedance, source impedance, or internal impedance of an electronic device is the opposition exhibited by its output terminals to the flow of an alternating current (AC) of a particular frequency as a result of resistance, induction and capacitance. ...
The input impedance or sometimes loading impedance of a circuit or electronic device is the impedance actually experienced by a signal which is connected to its input. ...
### Example If an amplifier produces an output of 1 volt into a 1 ohm load, then it is providing 1 watt of output power. If the amplifier is then altered to produce an output of 10 volts into the same load, it is now providing 100 watts of output power (*P*=*V*^{2}/*R*). Therefore: Josephson junction array chip developed by NIST as a standard volt. ...
Ohm may refer to: The scientist Georg Ohm. ...
voltage gain = 10 times power gain = 100 times — which by definition is said to be a gain of 20 dB. A gain of factor 1 or (equivalent to 0 dB) where both input and output are at the same voltage level is also known as *unity gain*. The word unity simply means oneness and is used in a variety of ways. ...
## See also |