Emitter Stabilized Bias Cicuit-Basic Electronics Biasing-Lecture Slides, Slides of Basic Electronics

Download Emitter Stabilized Bias Cicuit-Basic Electronics Biasing-Lecture Slides and more Slides Basic Electronics in PDF only on Docsity!

Basic Electronic Engineering

Lecture 14

Emitter-Stabilized Bias Circuit

• Emitter-stabilized circuit includes a resistor at the

emitter terminal

• This emitter resistor provides

improved temperature

stability over fixed bias

configuration

Collector-Emitter Loop

• Applying KVL on the loop
• Where

VCC  I RC C  VCE I RE E

I C  IE

V CE  VCC  IC (^)  RC  RE 

• Emitter Voltage (Voltage at emitter terminal)
• Collector Voltage (Voltage at collector terminal)
• Base Voltage (Voltage at base terminal)

VE  I RE E

VC  VCE VE

VC  VCC  I RC C

VB  VCC I RB B

VB  VBE VE

Improved Stability

• Compare the stability of fixed bias and emitter stabilized bias

circuit when β is varied from 50 to 100

(^00 2 4 6 8 10 12 14 16 18 )

1

2

3

4

5

Collector current Ic -->

Collector-Emitter voltage VCE -->

Beta 50 Fixed Bias

Beta 100 Fixed Bias

Beta 100 Emitter Bias

Beta 50 Emitte Bias

Load-line

CC C E

V R R

VCC

• Draw the load line for the network
• For a Q-point at the intersection on load line and IB=15μA find

the values on ICQ and VCEQ

• Determine the dc beta at Q-point
• Calculate the value of RB