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

What is the use of 8251 chip, What is the use of 8251 chip? 8251 chip i...

What is the use of 8251 chip? 8251 chip is mostly used as the asynchronous serial interface among the processor and the external equipment.

Explain the usage of the output ports , Objective: To Understand the Usage ...

Objective: To Understand the Usage of the Output ports of PIC18F452 and make changes in the previous code accordingly. Procedure: 1. Open the p1.asm program from t

Multiprocessing - many processors many users many programs , Multiprocessin...

Multiprocessing - Many Processors Many users Many Programs  Multiprocessing or also  called  distributed processing system  provides solution to problems of above  timesharing

Accelerator and investment, Q. Accelerator and Investment? Accelerator,...

Q. Accelerator and Investment? Accelerator, Investment: Investment spending stimulates economic growth that consecutively stimulates further investment spending (as businesses

Cipper, when i/p voltg is grater than battery diode is clse or open

when i/p voltg is grater than battery diode is clse or open

Production of rotating fields from single-phase windings, Production of Rot...

Production of Rotating Fields from Single-Phase Windings In this subsection we show that a single-phase winding carrying alternating current produces a stationary pulsating flu

Electronic instrumentation and measurements, why is a delay line used in th...

why is a delay line used in the vertical selection of oscilloscope?

What do you mean by phase sequence, Q. What do you mean by Phase Sequence? ...

Q. What do you mean by Phase Sequence? It is standard practice in the United States to designate the phase A-B-C such that under balanced conditions the voltage and current in

Determine the percentage ripple voltage, Problem (a) Figure gives the ...

Problem (a) Figure gives the basic circuit of the diode limiter. Assuming that the diodes are ideal sketch and annotate the waveforms of the input voltage vi(t) and the load

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