Ad
related to: amplifier definition in physics chemistry equation calculator
Search results
Results From The WOW.Com Content Network
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of a signal applied to its input ...
In physics, a quantum amplifier is an amplifier that uses quantum mechanical methods to amplify a signal; examples include the active elements of lasers and optical amplifiers. The main properties of the quantum amplifier are its amplification coefficient and uncertainty. These parameters are not independent; the higher the amplification ...
If the output is taken as a voltage, the amplifier is a transresistance amplifier and delivers a voltage dependent on the load impedance, for example v out = i in R L for a resistor load R L much smaller in value than the amplifier output resistance R out. That is, the voltage gain in this case (explained in more detail below) is
The power gain can be calculated using voltage instead of power using Joule's first law = /; the formula is: = . In many cases, the input impedance and output impedance are equal, so the above equation can be simplified to:
The amplifier's differential inputs consist of a non-inverting input (+) with voltage V + and an inverting input (−) with voltage V −; ideally the op amp amplifies only the difference in voltage between the two, which is called the differential input voltage. The output voltage of the op amp V out is given by the equation
Common-emitter amplifiers give the amplifier an inverted output and can have a very high gain that may vary widely from one transistor to the next. The gain is a strong function of both temperature and bias current, and so the actual gain is somewhat unpredictable.
A log amplifier, which may spell log as logarithmic or logarithm and which may abbreviate amplifier as amp or be termed as a converter, is an electronic amplifier that for some range of input voltage has an output voltage approximately proportional to the logarithm of the input:
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal n̂, d is the dipole moment between two point charges, the volume density of these is the polarization density P.