Conductance is the reciprocal of resistance. If it is taken between one output parameter and one input parameter, then it is called transconductance i. e. the ratio of output current to the input voltage.It is given by gm= Iout/Vin
voltage amplifier feedback current amplifier feedback transconductance feedback transresistance feedback
Roughly speaking, resistance. Transconductance refers to the reciprocal of the amplifying device's internal resistance. The concept is particularly useful if the device is a voltage-controlled current source (tube or FET). In vacuum tube amplifiers, transconductance (Gm) is (u / Rp), where... u is the amplification factor. u= (Gm x Rp). Rp is the anode (drain) resistance. Rp is the internal resistance of the amplifying device. Gfs is synonymous with Gm. The reciprocal of Gm (or Gfs) is (Rp / u). Another term for this reciprocal is transresistance.
gm0 is not used in BJT amplifier circuits; it is used in JFET circuits. It is the transconductance at zero gate bias. Since the transconductance varies as the bias is varied, this gives a benchmark level at a given defined point, and other transconductances can be calculated from it as a function of the amount of negative bias on the gate. If it were linear it would be the same everywhere, but it is not.
ApplicationsThe BJT remains a device that excels in some applications, such as discrete circuit design, due to the very wide selection of BJT types available, and because of its high transconductance and output resistance compared to MOSFETs. The BJT is also the choice for demanding analog circuits, especially for very-high-frequencyapplications, such as radio-frequency circuits for wireless systems. Bipolar transistors can be combined with MOSFETs in an integrated circuit by using a BiCMOSprocess of wafer fabrication to create circuits that take advantage of the application strengths of both types of transistor.
A: Transistors are really voltage amplifiers since the effect is voltage across a load. Using beta as a means to calculate gain is an approximation. basically is the ratio emitter resistor and collector resistor with no loadNo. Transistors (bipolar junction types, what most people think of as "transistor") are considered to be current devices.Although it's possible to specify a transconductance (output current/input voltage), this has not been done since the earliest days of transistor theory, and you will have trouble actually finding a transconductance specification in data sheets.Current gain is (output current/input current).In a common emitter circuit, this is (collector current/base current), known as hfe or "beta", with ranges from as low as 10 for high-current devices to high hundreds for low-power audio types.In common base, it's (collector current/emitter current), and it's just a bit less than 1.0, typically 0.95 to 0.999. This is known as hfb or "alpha".In common collector, it's (base current/emitter current), known as hfc, with about the same values as hfe.The exceptions are the obsolete point-contact types of the 1950s/early 1960s, and the various types of field-effect/MOS devices known variously as FETs, JFETs, IGFETs and MOSFETs.The field-effect/MOS devices have very low/zero input current, so they are not specified for current gains.
Usually output of an amplifier is a voltage ,...but in case of Operational Transconductance Amplifier ,Iout (current ) is the output. This feature, makes it useful for Electronic control of amplifier gain .
it is a transconductance unit which is "ampere/volt"
voltage amplifier feedback current amplifier feedback transconductance feedback transresistance feedback
Roughly speaking, resistance. Transconductance refers to the reciprocal of the amplifying device's internal resistance. The concept is particularly useful if the device is a voltage-controlled current source (tube or FET). In vacuum tube amplifiers, transconductance (Gm) is (u / Rp), where... u is the amplification factor. u= (Gm x Rp). Rp is the anode (drain) resistance. Rp is the internal resistance of the amplifying device. Gfs is synonymous with Gm. The reciprocal of Gm (or Gfs) is (Rp / u). Another term for this reciprocal is transresistance.
Whats is Hooke's law? How is the microprocessor 8085 architecture different ? What is ampere;'s transconductance?
gm0 is not used in BJT amplifier circuits; it is used in JFET circuits. It is the transconductance at zero gate bias. Since the transconductance varies as the bias is varied, this gives a benchmark level at a given defined point, and other transconductances can be calculated from it as a function of the amount of negative bias on the gate. If it were linear it would be the same everywhere, but it is not.
With straight electronics, one way to design a multiplier circuit would be with an operational transconductance amplifier, such as the CA3080, with one input driving the input pin and the other driving the gain control pin. This can be biased and calibrated to perform multiplication. Another way is to use a four quadrant multiplier chip, such as the AD834, which is based on transconductance as well, but designed specifically for multiplication. With a microcontroller, a better solution in low frequency applications, you can read the two inputs with two analog to digital converter inputs, multiply those values in software (applying whatever offset and calibration desired) and send the output to an digital converter output.
No, equal changes in Vgs do not necessarily cause equal changes in Id for a MOSFET. The relationship between Vgs and Id is nonlinear and depends on the characteristics of the specific MOSFET being used, such as threshold voltage and transconductance. The current-voltage relationship in a MOSFET is governed by its operating region (ohmic, saturation, or cutoff).
Diffusion capacitance is the capacitance due to transport of charge carriers between two terminals of a device. - Amog This diffusion capacitance is due to depletion capacitance which is a function of forward bias applied to emitter junction of a transistor and due to diffusion capacitance which a function of transconductance of the transistor. Its value is 100 pF. Tirupanyam B.V
comparison between cmos and bipolar technologiescmos technologies:low static power dissipationhigh input impedancescalable threshold voltagehigh noise marginhigh packing densityhigh delay sensitivity to load(fan out limitations)low output drive currentlow transconductance(gm)bidirectional capabilitydrain and source are interchangeblea near ideal switching devicefully restored logic levelsbipolar technology:high power dissipationlow input impedancelow voltage swing logiclow packing densitylow delay sensitivity to loadhigh output drive currenthigh transconductanceunidirectional
ApplicationsThe BJT remains a device that excels in some applications, such as discrete circuit design, due to the very wide selection of BJT types available, and because of its high transconductance and output resistance compared to MOSFETs. The BJT is also the choice for demanding analog circuits, especially for very-high-frequencyapplications, such as radio-frequency circuits for wireless systems. Bipolar transistors can be combined with MOSFETs in an integrated circuit by using a BiCMOSprocess of wafer fabrication to create circuits that take advantage of the application strengths of both types of transistor.
Transfer Characteristic of JFETThe transfer characteristic for a JFET can be determined experimentally, keeping drain-source voltage, VDSconstant and determining drain current, ID for various values of gate-source voltage, VGS. The circuit diagram is shown in fig. 9.7 (a). The curve is plotted between gate-source voltage, VGS and drain current, ID, as illustrated in fig. 9.8. It is similar to the transconductance characteristic of a vacuum tube or a transistor. It is observed that (i) Drain current decreases with the increase in negative gate-source bias(ii) Drain current, ID = IDSS when VGS = 0(iii)Drain current, ID = 0 when VGS = VD The transfer characteristic follows equation (9.1)The transfer characteristic can also be derived from the drain characteristic by noting values of drain current, ID corresponding to various values of gate-source voltage, VGS for a constant drain-source voltage and plotting them.It may be noted that a P-channel JFET operates in the same way and have the similar characteristics as an N-channel JFET except that channel carriers are holes instead of electrons and the polarities of VGS and VDSare reversed.