Amplifier with Mosfet - DIGITAL ELECTRONIC PDF

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Summary

DIGITAL ELECTRONIC...

Description

Introduction A MOSFET is a semiconductor device used for switching and amplifying signals. The full name, Metal-Oxide-Semiconductor Field Effect Transistor is due to the constitution of the transistor itself. When we were talking about BJTs, we mentioned that there are 2 types of transistors, NPN and PNP and that they have 3 terminals: the base, the collector and the emitter. The MOSFETs also have 3 terminals: Gate, Drain and Source.

Task objective. The objective of the task is to analyze and understand the behavior of the MOSFET transistor as an amplifier, the corresponding calculations will be carried out to know its voltage output in order to better compare them with the simulation carried out in the MULTISIM program, to corroborate the data obtained through the elaborated calculations. , as well as graphing the curve and finding the Q point of the transistor.

Mathematical analysis MOSFET amplification Direct current analysis For the amplifier with E - MOSFET and polarized by voltage divider. Determine the output voltage V0. You have the following data:

VGS (Th) = 2V, Vgs (on)= 10V, IDON)= 1A, and gm= 7.49mS

K =

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� �= � (�� � ))� − �� )

�

(��� (�� −��� ) (��

=

Equation for the transfer curve

IDQ = (VGSQ - BGS (Th)) = 15.6m

�

15.6m �� �

(VGSQ - 2V) 2

��

VG = VDD � �= 12V � ��+ ��

�

��

= 3.43V

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Equation for the polarization line

VGS = VG - IDRS We obtain the point Q at

IDQ = 897µA and VGSQ = 2.24V VDS = VDD - IDQ (RD + RS) = 12V - 897µA (8.3KΩ) = 4.55V VS = IDQRS = 897µA (1.5KΩ) = 1.35V VD = VDD - IDQRD = 12V - 897µA (638KΩ) = 5.9V

Alternating current analysis

Zin = || R2 = 5MΩ || 2MΩ = 1.43MΩ Z0 ≈RD = 6.8KΩ AV = -GmRD = -7.49mS (6.8KΩ) = -51 VinX = Vin

���

���+ ���

= 49.99mVp

= 50mV �.���� �

�.���� � ��� �

+

AVVinX = 51 (49.99mVp) = -2.55Vp V0 = AVVinX �� = -2.55Vp ���� � ��+ ��

��.�� � �

= 1.9 Vp

Direct Current Simulation.

Measurements made in Multisim. Direct current.

VD = 7.155V VS = 1.069V VDS 6.086V

=

Simulation. Alternating Current For VinX

To V0

Measurements made in Multisim.

For VinX

VinX = 49.499mV

To V0

V0 = 1.865V

Value table

Direct current

YOU

Calculated value 5.9V

Measured value 7.155V

VS

1.35V

1.069V

VDS

4.55V

6.086V

Alternating current

Calculated value VinX

49.99mVp

Measured value 49.499mV

V0

1.9 Vp

1.865V

conclusion To conclude with this task, I observed that when measuring with an oscilloscope and when comparing it with the multimeter the values were wrong or very different, then I realized that it was because of the values so small and the multimeter could not distinguish them, this This task helped me to understand more how the circuits work, as well as the simulations made in multisim....