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drain resistane is basically the resistance offered by the drain terminal of the fet device.its the ratio of change in drain to source voltage to the change in drain current at a constant gate to source voltage.
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What is the voltage gain of the FET amplifier?
It can be answered in two ways : 1. ratio of output & input voltages [Vout / Vin] i.e Drain voltage(Vds)/Source voltage(Vs). 2. multiplication of trans-conductance & drain resistance .
How fet is used as vvr?
FET AS A VOLTAGE -VARIABLE RESISTOR (VVR):FET is operated in the constant current portion of its output characteristics for the linear applications .In the region before pinch off , where Vds is small the drain to source resistance rd can be controlled by the bias voltage Vgs.The FET is useful as a voltage variable resistor (VVR) or Voltage Dependent resistor.In JFET the drain source conductance gd = Id/Vds for small values of Vds which may be expressed as gd = gdo [ 1-( VgsVp)1/2 ] where gdo is the value of drain conductance when the bias voltage Vgs is zero.The variation of the rd with vgs can be closely approximated by rd = ro / 1- KVgs ro - drain resistance at zero gate bias and K constant dependent upon FET type.Small signal FET drain resistance rd varies with applied gate voltage Vgs and FET act like a VARIABLE PASSIVE RESISTOR.Advantagesof JFETVery high input impedance order of 100 ohmOperation of JFET depends on the bulk material current carriers that do not cross junctionsNegative temperature coefficientsVery high power gainSmaller size longer life and high efficiencyAc drain resistance rd it is the ratio of change in drain - source voltage to the change in drain current at constant gate source voltageTransconductance it is the ratio of change in drain current to the change in gate source voltageat constant drain source voltageAmplification factor it is the ratio of change in drain source voltage to the change in gate source voltage at constant drain current.
Explain the origin of finite output resistance of MOSFET devices?
let the mosfet be biased in saturation regior. thus drain current in independent of drain to sourse voltage, the VI chara. is a curve, when this is extended till X axis at pt. Vds=-Va this is similar to effect in transistor the o/p resistance is slope of V-I chara.. it should ideally be infinite, but has some finite value due to "CHANNEL LENGTH MODULATION"
What is the inverse of transconductance?
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.
Dc resistance of diode is a static resistance b dynamic resistance c high resistance d zero resistance?
B - Dynamic resistance
Is fet having negative resistance?
JFET BFW20 shows negetive resistance when gate is grounded (VGS = 0) and vary Drain to source voltage and measure Drain current. As the voltage is increased, the drain current decreases. Prof.S.Lakshminarayana.
What are the parameters of fet?
drain resistance (rd) amplification factor trans conductance
Why does a short circuit drain a battery?
You have to remember ohms law Voltage = amp * resistance. Using some basic algebra you can rewrite the equation as amps = voltage / resistance. Since a short circuit has relatively 0 ohms of resistance, this increases both the amps and resistance which uses more battery capacity,power, and creates more heat.
What is the voltage gain of the FET amplifier?
It can be answered in two ways : 1. ratio of output & input voltages [Vout / Vin] i.e Drain voltage(Vds)/Source voltage(Vs). 2. multiplication of trans-conductance & drain resistance .
What is the influence of gate voltage on drain source breakdown voltage in mos transistors?
Drain-to-source breakdown voltage (BVdss) should not change appreciably until the gate-to-source voltage (Vgs) approaches the device's threshold voltage (Vth). In that case, the drain to source voltage becomes the product of the drain-to-source current (Ids) and the device's on-state resistance (Rds-on) at the given Vgs.
How fet is used as vvr?
FET AS A VOLTAGE -VARIABLE RESISTOR (VVR):FET is operated in the constant current portion of its output characteristics for the linear applications .In the region before pinch off , where Vds is small the drain to source resistance rd can be controlled by the bias voltage Vgs.The FET is useful as a voltage variable resistor (VVR) or Voltage Dependent resistor.In JFET the drain source conductance gd = Id/Vds for small values of Vds which may be expressed as gd = gdo [ 1-( VgsVp)1/2 ] where gdo is the value of drain conductance when the bias voltage Vgs is zero.The variation of the rd with vgs can be closely approximated by rd = ro / 1- KVgs ro - drain resistance at zero gate bias and K constant dependent upon FET type.Small signal FET drain resistance rd varies with applied gate voltage Vgs and FET act like a VARIABLE PASSIVE RESISTOR.Advantagesof JFETVery high input impedance order of 100 ohmOperation of JFET depends on the bulk material current carriers that do not cross junctionsNegative temperature coefficientsVery high power gainSmaller size longer life and high efficiencyAc drain resistance rd it is the ratio of change in drain - source voltage to the change in drain current at constant gate source voltageTransconductance it is the ratio of change in drain current to the change in gate source voltageat constant drain source voltageAmplification factor it is the ratio of change in drain source voltage to the change in gate source voltage at constant drain current.
How much current does a size D battery have?
Doesn't work like that. Current drain is dependent on the (internal resistance of the battery and the) resistance/power requirements of what's connected to the battery. If shorted out, the current - unless the battery is fused or otherwise protected - can go into tens of amps.
How does the Analog multiplexer IC-4051 works?
I think each channel acts like a drain-source path of a FET switch,whose resistance changes from very high to very low. Yet the Drain - source are almost isolated from gate. It seems internally the a.multiplexer contains such FETs. And depending upon the channel selection by digital pins a0..a2 certain single path is made low resistance
How does the Analog multiplexer IC 4051 works?
I think each channel acts like a drain-source path of a FET switch,whose resistance changes from very high to very low. Yet the Drain - source are almost isolated from gate. It seems internally the a.multiplexer contains such FETs. And depending upon the channel selection by digital pins a0..a2 certain single path is made low resistance
Explain the origin of finite output resistance of MOSFET devices?
let the mosfet be biased in saturation regior. thus drain current in independent of drain to sourse voltage, the VI chara. is a curve, when this is extended till X axis at pt. Vds=-Va this is similar to effect in transistor the o/p resistance is slope of V-I chara.. it should ideally be infinite, but has some finite value due to "CHANNEL LENGTH MODULATION"
How does a vent prevent siphonage?
The soil vent in the waste line breaks the siphon that would drain traps and toilet bowls by providing a path of least resistance for air pressure. see link
Why input is voltage and output is current in fet?
The input is a Gate that is essentially infinite impedance, so no current. The output is essentially the resistance between Source and Drain, which controls the current flowing through it.
