measuring transconductance(gm)
How do u measure Transconductance?
Transconductance is the Ratio of output current to the input voltage
The Bias Current changes the Transconductance(gm) in microseconds or milliseconds in time?
The Bias Current changes the input and output impedance why and how?
(the input and output decrease as the bias current increases)
whats the difference between conductance VS transconductance?
conductances means how fast current flows?
Transconductance means ?
Re: measuring transconductance(gm)
why should we..?Originally Posted by walters
correctTransconductance is the Ratio of output current to the input voltage
:shock:The Bias Current changes the Transconductance(gm) in microseconds or milliseconds in time?
akg
Can u give me a Water analogy for "colour" in electronics ? what is "Colour water" in electronics?
What would be the water analogy for transconducance?
similar to a Dam , heigher the water (more pressure at bottom/voltage), more the water discharge from bottom (flow/current)
Thanks alot akg
Re: measuring transconductance(gm)
My answers are all in the 1st few links in Google. Why didn't you look there?
No. Transconductance is the Ratio of the change of output current to the change of input voltage. This corrected description answers your 1st question.
Time has nothing to do with it. It is immediate. Transconductance is measured with a voltage input, not a bias current input.The Bias Current changes the Transconductance(gm) in microseconds or milliseconds in time?
A lower impedance is required in order to pass more current.The Bias Current changes the input and output impedance why and how?
(the input and output decrease as the bias current increases)
Conductance is a resistance. Transconductance is a voltage-controlled resistance.whats the difference between conductance VS transconductance?
No. Current flows a little or a lot at only one speed. Current is a quantity of amps. A low conductance passes a low current. A high conductance passes a high current.conductances means how fast current flows?
Uncle $crooge
Thanks alot for the information and correcting me
What does (Gm) mean? they say in books that transconductance=gm
They say in my Book that Gm=time
example in my book
"The output current of an OTA is the input voltages times the transconductance"
OTA has a gm=1000us
What is the output currrent when the input voltage is 25mV
(Gm)(Vin)= I out
(1000us)(25mV)=25uA
Quote:
whats the difference between conductance VS transconductance?
Conductance is a resistance. Transconductance is a voltage-controlled resistance.
Transconductance= voltage controlled resistance
GM= Time
Does treansconductance= Gm
Transconductance internet notes::
a bipolar device, transconductance is defined as the ratio of the change in collector current to the change in base voltage over a defined, arbitrarily small interval on the collector-current-versus-base-voltage curve. For an FET, transconductance is the ratio of the change in drain current to the change in gate voltage over a defined, arbitrarily small interval on the drain-current-versus-gate-voltage curve.
The symbol for transconductance is gm.
If dI represents a change in collector or drain current caused by a small change in base or gate voltage dE, then the transconductance is approximately:
gm = dI / dE
As the size of the interval approaches zero -- that is, the change in base or gate voltage becomes smaller and smaller -- the value of dI / dE approaches the slope of a line tangent to the curve at a specific point. The slope of this line represents the theoretical transconductance of a bipolar transistor for a given base voltage and collector current, or the theoretical transconductance of an FET for a given gate voltage and drain current.
Transconductance is a measure of the change in plate current to a change in grid voltage, with plate voltage held constant. The unit for conductance is the mho (siemens), pronounced "moe." Transconductance is normally expressed in either micromhos or millimhos.
Transconductance, also known as mutual conductance, is a property of certain electronic components. It is a contraction of "transfer conductance". Conductance is the flow of a current through two points when a voltage is applied as in a resistor, conductance being the reciprocal of resistance. In contrast, transconductance is the control of a current through two output points by a voltage at two input points, as if the conductance is transferred from the input points to the output points. When referring to a value, it is the ratio between these changes in voltage and current, and is written as gm:
In the world of vacuum tubes, transconductance is 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 gm for a small-signal vacuum tube are 1 to 10 millisiemens.
Similarly, in field effect transistors, transconductance is the change in the drain/source current divided by the change in the gate/drain voltage with a constant drain/source voltage. Typical values of gm for a small-signal field effect transistor are also 1 to 10 millisiemens.
The gm of bipolar small-signal transistors varies widely, increasing exponentially with the emitter 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.
A transconductance amplifier outputs a current proportional to its input voltage.
the ratio of the tubes plate current to its grid voltage. The unit of transconductance is the "mho", which is measured in amps/volt, and is not surprisingly "ohm" spelled backwards, because one ohm is equal to one volt divided by one amp, so the unit of resistance, the ohm, is a volt/amp. Transconductance is one "figure of merit" for a tube. Higher transconductances mean higher gains and greater amplification from the tube.
sorry walters , i missed a change
its ok thanks for the help anyway
