Fixed bias with emitter resistor, Electrical Engineering

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.

Posted Date: 1/10/2013 7:20:15 AM | Location : United States







Related Discussions:- Fixed bias with emitter resistor, Assignment Help, Ask Question on Fixed bias with emitter resistor, Get Answer, Expert's Help, Fixed bias with emitter resistor Discussions

Write discussion on Fixed bias with emitter resistor
Your posts are moderated
Related Questions
Planned and coordinated development: The CEA would prepare the global Electricity Plan after carefully carrying out the demand forecast in consultation along with stakeholders

Q. Consider an elementary three-phase, four-pole alternator with a wye-connected armature winding, consisting of full-pitch concentrated coils.  Each phase coil has three turns,

delta connectino purpose

Explain Extrinsic Semiconductor. Extrinsic Semiconductor: An intrinsic semiconductor is able to conduct some current even at room temperature but as this is not helpful for t

A circular ring of magnetic material has a mean length of 1m and a cross sectional area of .001m^2.A sawcut of 5mm width is made in the ring . calculate the magnetizing current req

Q. For a p-channel JFET in its active region, specify the polarities of voltages and the directions of conventional currents.

What is mgnomotive force

Q. Draw the developed diagram of a simplex progressive 2 layer lap winding for a 4 pole generator with 12 coils clearly indicating the position of brushes.   Sol.  No. o

Three equal impedances of D ohms resistance and C inductive reactance are connected in a DELTA configuration. The line voltage is A00 volts. Determine the line current, phase cur

Q. Give a brief description of integrating circuits ? Integration is a summation of area. An integrating circuit produces an output voltage which is proportional to the area en