Fixed bias with emitter resistor, Electrical Engineering

Assignment Help:

Fixed bias with emitter resistor:

711_Usage.png

Figure: Fixed bias with emitter resistor

The fixed bias circuit is changed through attaching an external resistor to the emitter. This resistor establishes negative feedback which stabilizes the Q-point. From the voltage law of Kirchhoff, the voltage across the base resistor is

VRb = VCC - IeRe - Vbe.

From the law of Ohm, the base current is

Ib = VRb / Rb.

The manner feedback controls the bias point is like this. If Vbe is stay constant and temperature get increases, emitter current also increases. Though, a larger Ie increases the emitter voltage Ve = IeRe, in turn which decreases the voltage VRb across the base resistor. A lower base-resistor voltage drop decreases the base current that results in less collector current since Ic = ß IB. Collector current and emitter current are related through the Ic = α Ie with α ≈ 1, thus an increase in emitter current with temperature is opposed, and operating point is kept stable.


Related Discussions:- Fixed bias with emitter resistor

Equivalent circuit of a field-effect transistor, Q. The circuit shown in Fi...

Q. The circuit shown in Figure is the equivalent circuit of a field-effect transistor (FET) amplifier stage. (a) Determine the y-parameters. (b) For values of µ = g m /g d >

Determine briefly subscriber loop system, Q. Determine briefly subscriber l...

Q. Determine briefly subscriber loop system.  Give some technical specification for subscriber lines. Ans: Subscriber Loop System: Each subscriber in a telephone network is

Show maximum common-mode input voltage, Q. Show Maximum Common-Mode Input V...

Q. Show Maximum Common-Mode Input Voltage of amplifier? This is the maximum voltage that the two inputs can be raised above ground potential before the op amp becomes nonlinear

Problem of current electricity, charges of +2q and -4q are fixed a distance...

charges of +2q and -4q are fixed a distance d apart as in figure_2(a).find electric field at the point A ,B and C (b) sketch roughly the electric field lines.

Calculate armature voltage, Question: A DC, separately excited motor is...

Question: A DC, separately excited motor is supplied from a 240-V source. When the motor is unloaded, it draws 1A of current from the source. When the motor is loaded, it draws

How linear sweep voltage is generated, Q. With a suitable block circuit, sh...

Q. With a suitable block circuit, show how linear sweep voltage is generated ? The above figure shows a basic sweep waveform generator. The switching action of the switch

Resistance, factors affecting resistance

factors affecting resistance

Minimize f in a pos form and obtain a possible realization, Q. The truth ta...

Q. The truth table for F(A,B,C) = Mi (0, 1, 6, 7) is as follows: (a) Express F in a canonical product-of-sums form. (b) Minimize F in a POS form and obtain a possible re

Ldax load accumulator indirect instruction , LDAX  Load Accumulator Indire...

LDAX  Load Accumulator Indirect Instruction This instruction is used to copy data  from memory  location pointed by register  pair only  BC or DE  to the accumulator  HL pair

Variation of energy bands with alloy composition, Variation of Energy Bands...

Variation of Energy Bands with Alloy Composition The  band  structures  of  III-V  ternary  and  quaternary  compounds  modifies  as  their composition is varied. There

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd