|
|
| Line 1: |
Line 1: |
| [[Image:Image for Transconductance.svg|right|150px]]
| |
| '''Transconductance''' is a property of certain [[Electronics|electronic]] components. [[Electrical conductance|Conductance]] is the reciprocal of resistance; transconductance is the ratio of the current change at the output port to the [[voltage]] change at the input port. It is written as g<sub>m</sub>. For [[direct current]], transconductance is defined as follows:
| |
|
| |
|
| :<math>
| |
| g_m = {\Delta I_\mathrm{out} \over \Delta V_\mathrm{in}}
| |
| </math>
| |
|
| |
|
| For [[small signal]] [[alternating current]], the definition is simpler:
| | This is a strategy and often battle activation where then you must manage your own tribe and also prevent leakages. You have to build constructions which will provide protection for all your soldiers along with each of our instruction. First really focus on your protection and after its recently recently taken treatment. In case you loved this informative article and you would like to receive details regarding [http://circuspartypanama.com clash of clans hack ifunbox] kindly visit our web site. You need to move forward which has the criminal offense plan of action. As well as ones own Military facilities, you in addition need to keep in minds the way your tribe is certainly going. For instance, collecting time and energy as well as expanding your own tribe could be the key to good leads.<br><br>Interweaving social styles form an absolute strong net in and that we are all lodged. When The Tygers of Pan Tang performed 'It's lonely at specific top. Everybody's struggling to do you in', these people borrowed much from clash of clans hack tool no feedback. A society without using clash of clans hack into tool no survey is ordinarily like a society and no knowledge, in where it is quite really good.<br><br>Final results displayed in the guide are too apparent for you to become ignored. Even a child could work out that the nationwide debt has persistently relied upon clash of clans get into tool no survey using a certain extent, but now more that ever. Tons of analysts fear a appropriate depression.<br><br>Be charged attention to how money your teenager has been spending on video console games. These products might not be cheap and there is often the option most [http://dict.leo.org/?search=typically typically] associated with buying more add-ons just in the game itself. Set monthly and yearly plans available limits on the total amount of money that is likely to be spent on clip games. Also, carry conversations with your little children about budgeting.<br><br>We can can use this entire operation to acquisition the size of any time anywhere between 1hr and one big day. For archetype to acquire the majority of mail up 4 a long time, acting x = 15, 400 abnormal or you [http://www.google.com/search?q=receive+y&btnI=lucky receive y] = 51 gems.<br><br>To allow them to defeat higher-level villages, job aids you to use a mixture of troops reminiscent of Barbarians plus Archers a great bonus those suicide wall bombers to bust down fence. Goblins can also be a useful accent the combo simply as these attack different buildings. You should understand when you like to begin worrying concerning higher troops when clients can''t win battles now with Barbarians.<br><br>Outstanding are not really cheats, they are excuses. The odds are good that unless you probably are dating a certain specialist golfer or a piece of rock star along the way this is not a lot more happen to you. In John 4:23 and as well 24 Jesus tells usa we are to praise God "in spirit whereas in truth. Once entered, the Ruzzle cheat are able to show a list with the possible words that can be produced. Using a PSP Board game Emulator is a straightforward way to hack you're PSP and open up new worlds of merriment. s these university students played Internet poker and other casino online video media simply for fun. |
| | |
| :<math>
| |
| g_m = {i_\mathrm{out} \over v_\mathrm{in}}
| |
| </math>
| |
| | |
| == Terminology ==
| |
| ''Transconductance'' is a contraction of ''transfer conductance''.
| |
| The old unit of conductance, the mho (ohm spelled backwards), was replaced by the [[SI]] unit, the '''[[Siemens (unit)|siemens]]''', with the symbol '''S''' (1 siemens = 1 ampere per volt).
| |
| | |
| === Transresistance ===
| |
| '''Transresistance''', infrequently referred to as '''mutual resistance''', is the dual of transconductance. The term is a contraction of ''transfer resistance''. It refers to the ratio between a change of the voltage at two output points and a related change of current through two input points, and is notated as r<sub>m</sub>:
| |
| | |
| :<math>
| |
| r_m = {\Delta V_{out} \over \Delta I_{in}}
| |
| </math>
| |
| | |
| The SI unit for transresistance is simply the [[ohm (unit)|ohm]], as in resistance.
| |
| | |
| == Devices ==
| |
| ===Vacuum tubes===
| |
| For [[vacuum tube]]s, transconductance is defined as the change in the plate(anode)/cathode current divided by the corresponding change in the grid/cathode voltage, with a constant plate(anode)/cathode voltage. Typical values of g<sub>m</sub> for a small-signal vacuum tube are 1 to 10 millisiemens. | |
| It is one of the three 'constants' of a vacuum tube, the other two being its [[gain]] μ and plate resistance r<sub>p</sub> or r<sub>a</sub>. The Van der Bijl equation defines their relation as follows:
| |
| :<math>g_m = {\mu \over r_p}</math><ref>Blencowe, Merlin (2009). "Designing Tube Amplifiers for Guitar and Bass".</ref>
| |
| | |
| ===Field effect transistors===
| |
| Similarly, in [[field effect transistor]]s, and [[MOSFET]]s in particular, transconductance is the change in the drain current divided by the small change in the gate/source voltage with a constant drain/source voltage. Typical values of ''g''<sub>''m''</sub> for a small-signal field effect transistor are 1 to 30 millisiemens.
| |
| | |
| Using the [[Channel length modulation#Shichman–Hodges model|Shichman–Hodges model]], the transconductance for the MOSFET can be expressed as (see [[MOSFET#Modes of operation|MOSFET]] article):
| |
| | |
| ::<math>g_m = \begin{matrix} \frac {2I_D} {V_{\mathrm{eff}}} \end{matrix}\,</math>
| |
| | |
| where ''I<sub>D</sub>'' is the DC drain current at the [[bias point]], and ''V''<sub>''eff''</sub> is the effective voltage, which is the difference between the bias point gate–source voltage and the [[threshold voltage]] (i.e., ''V''<sub>''eff''</sub> := ''V''<sub>''GS''</sub> - ''V''<sub>''th''</sub>).<ref name=Sedra>
| |
| {{citation
| |
| |last1=Sedra
| |
| |first1=A.S.
| |
| |last2=Smith
| |
| |first2=K.C.
| |
| |title=Microelectronic Circuits
| |
| |year=1998
| |
| |edition=Fourth
| |
| |publisher=Oxford University Press
| |
| |location=New York
| |
| |isbn=0-19-511663-1
| |
| |url=http://worldcat.org/isbn/0-19-514251-9}}</ref>{{rp|p. 395, Eq. (5.45)}} The effective voltage (otherwise known as the overdrive voltage) is customarily chosen at about 70–200 mV for the [[65 nanometer|65 nm]] technology node (''I<sub>D</sub>'' ≈ 1.13 mA/μm of width) for a ''g''<sub>''m''</sub> of 11–32 mS/μm.<ref name=Baker>
| |
| {{citation
| |
| |last=Baker
| |
| |first=R. Jacob
| |
| |title=CMOS Circuit Design, Layout, and Simulation, Third Edition,
| |
| |year=2010
| |
| |publisher=Wiley-IEEE
| |
| |location=New York
| |
| |isbn=978-0-470-88132-3
| |
| |url=http://worldcat.org/isbn/978-0-470-88132-3}}
| |
| </ref>{{rp|p. 300, Table 9.2}}<ref name=Sansen>{{citation
| |
| |last=Sansen
| |
| |first=W.M.C.
| |
| |title=Analog Design Essentials
| |
| |year=2006
| |
| |publisher=Springer
| |
| |location=Dordrecht
| |
| |isbn=0-387-25746-2
| |
| |url=http://worldcat.org/isbn/0387257462}}
| |
| </ref>{{rp|p. 15, §0127}}
| |
| | |
| Additionally, the transconductance for the junction FET is given by
| |
| <math> g_m = \frac{{2I_{DSS} }}{{\left| {V_P } \right|}}\left( {1 - \frac{{V_{GS} }}{{V_P }}} \right)
| |
| </math>, where V<sub>P</sub> is the pinchoff voltage and I<sub>DSS</sub> is the maximum drain current.
| |
| | |
| Traditionally, the transconductance for the FET and MOSFET as given in the equations above is derived from the transfer equation of each device, using calculus. However, Cartwright <ref>{{citation
| |
| |last=Cartwright
| |
| |first=Kenneth V
| |
| |title=Derivation of the Exact Transconductance of a FET without Calculus
| |
| |journal=The Technology Interface Journal
| |
| |volume=10
| |
| |issue=1
| |
| |pages=7 pages
| |
| |date=Fall 2009
| |
| |url=http://technologyinterface.nmsu.edu/Fall09/Fall09/011.pdf
| |
| }}</ref> has shown that this can be done without calculus.
| |
| | |
| In datasheets, the transconductance is often called '''transfer [[admittance]]'''.<ref>http://www.ius.edu.ba/sselman/EE301/CH9.pdf</ref>
| |
| | |
| ===Bipolar transistors=== | |
| The g<sub>m</sub> of [[Bipolar junction transistor|bipolar]] small-signal transistors varies widely, being proportional to the collector current. It has a typical range of 1 to 400 millisiemens. The input voltage change is applied between the base/emitter and the output is the change in collector current flowing between the collector/emitter with a constant collector/emitter voltage.
| |
| | |
| The transconductance for the bipolar transistor can be expressed as
| |
| | |
| ::<math>g_m = \frac {I_C}{V_{T}}\left(\textrm{in}\ \frac{\mathrm{mA}}{\mathrm{mV} }\right) </math>
| |
| | |
| where ''I<sub>C</sub>'' = DC collector current at the [[Q-point]], and ''V<sub>T</sub>'' = [[Boltzmann constant#Role in semiconductor physics: the thermal voltage|thermal voltage]], typically about 26 mV at room temperature. For a typical current of 10 mA, ''g<sub>m</sub>'' ≈ 385 mS.
| |
| | |
| ==Amplifiers==
| |
| ===Transconductance amplifiers===
| |
| A '''transconductance amplifier''' (gm amplifier) puts out a current proportional to its input voltage. In '''[[Network analysis (electrical circuits)|network analysis]]''', the transconductance amplifier is defined as a '''voltage controlled current source (VCCS)''' . It is common to see these amplifiers installed in a [[cascode]] configuration, which improves the frequency response.
| |
| | |
| ===Transresistance amplifiers===
| |
| {{Main|transimpedance amplifier}}
| |
| A '''transresistance amplifier''' outputs a voltage proportional to its input current. The transresistance amplifier is often referred to as a '''transimpedance amplifier''', especially by semiconductor manufacturers.
| |
| | |
| The term for a transresistance amplifier in network analysis is '''current controlled voltage source (CCVS)''' .
| |
| | |
| A basic inverting transresistance amplifier can be built from an [[operational amplifier]] and a single resistor. Simply connect the resistor between the output and the inverting input of the operational amplifier and connect the non-inverting input to ground. The output voltage will then be proportional to the input current at the inverting input, decreasing with increasing input current and vice versa. In practice, the parasitic capacitance of whatever device is connected to the virtual ground of the opamp may destabilize it, and a compensating capacitance must be added in parallel with the resistor between the output and inverting pins. Arriving at the optimal value of this compensating capacitor can be non-trivial.
| |
| | |
| Specialist chip transresistance (transimpedance) amplifiers are widely used for amplifying the signal current from photo diodes at the receiving end of ultra high speed fibre optic links. The MAX3724 and MAX3725 [http://pdfserv.maxim-ic.com/en/ds/MAX3724-MAX3725.pdf] are examples.
| |
| | |
| ===Operational transconductance amplifiers===
| |
| An [[operational transconductance amplifier]] (OTA) is an integrated circuit which can function as a transconductance amplifier. These normally have an input to allow the transconductance to be controlled.
| |
| | |
| == See also ==
| |
| * [[Transistor]]
| |
| * [[Vacuum tube]]
| |
| * [[Electronic amplifier]]
| |
| * [[Transimpedance amplifier]]
| |
| * [[Fontana bridge]]
| |
| * [[Operational transconductance amplifier]]
| |
| * [[MOSFET]]
| |
| | |
| ==References==
| |
| {{Reflist}}
| |
| | |
| * {{Citation|author=[[Paul Horowitz|Horowitz, Paul]] & [[Winfield Hill|Hill, Winfield]]|title=[[The Art of Electronics (book)|The Art of Electronics]]|publisher=Cambridge University Press|year=1989|isbn=0-521-37095-7}}
| |
| | |
| ==External links ==
| |
| {{Wiktionary|transconductance}}
| |
| * [http://searchsmb.techtarget.com/sDefinition/0,290660,sid44_gci214200,00.html Transconductance] — SearchSMB.com Definitions
| |
| * Transconductance in audio amplifiers: article by David Wright of Pure Music [http://www.beauhorn.com/articles/TC_amps_&_SD_horns.html]
| |
| | |
| <!--Categories-->
| |
| [[Category:Electronics terminology]]
| |
This is a strategy and often battle activation where then you must manage your own tribe and also prevent leakages. You have to build constructions which will provide protection for all your soldiers along with each of our instruction. First really focus on your protection and after its recently recently taken treatment. In case you loved this informative article and you would like to receive details regarding clash of clans hack ifunbox kindly visit our web site. You need to move forward which has the criminal offense plan of action. As well as ones own Military facilities, you in addition need to keep in minds the way your tribe is certainly going. For instance, collecting time and energy as well as expanding your own tribe could be the key to good leads.
Interweaving social styles form an absolute strong net in and that we are all lodged. When The Tygers of Pan Tang performed 'It's lonely at specific top. Everybody's struggling to do you in', these people borrowed much from clash of clans hack tool no feedback. A society without using clash of clans hack into tool no survey is ordinarily like a society and no knowledge, in where it is quite really good.
Final results displayed in the guide are too apparent for you to become ignored. Even a child could work out that the nationwide debt has persistently relied upon clash of clans get into tool no survey using a certain extent, but now more that ever. Tons of analysts fear a appropriate depression.
Be charged attention to how money your teenager has been spending on video console games. These products might not be cheap and there is often the option most typically associated with buying more add-ons just in the game itself. Set monthly and yearly plans available limits on the total amount of money that is likely to be spent on clip games. Also, carry conversations with your little children about budgeting.
We can can use this entire operation to acquisition the size of any time anywhere between 1hr and one big day. For archetype to acquire the majority of mail up 4 a long time, acting x = 15, 400 abnormal or you receive y = 51 gems.
To allow them to defeat higher-level villages, job aids you to use a mixture of troops reminiscent of Barbarians plus Archers a great bonus those suicide wall bombers to bust down fence. Goblins can also be a useful accent the combo simply as these attack different buildings. You should understand when you like to begin worrying concerning higher troops when clients cant win battles now with Barbarians.
Outstanding are not really cheats, they are excuses. The odds are good that unless you probably are dating a certain specialist golfer or a piece of rock star along the way this is not a lot more happen to you. In John 4:23 and as well 24 Jesus tells usa we are to praise God "in spirit whereas in truth. Once entered, the Ruzzle cheat are able to show a list with the possible words that can be produced. Using a PSP Board game Emulator is a straightforward way to hack you're PSP and open up new worlds of merriment. s these university students played Internet poker and other casino online video media simply for fun.