Common Emitter Configuration

the configuration of a transistor circuit in which emitter is grounded or made common in input loop and output loop of circuit is common emitter configuration.

Current:

in the current IE Ib and Ic flows due to external voltage source through emitter base and collector. when transistor connected in common emitter configuration.

Voltage:

that transistor consists of two diode;
1. emitter diode
2. collector diode
silicone based diode has barrier potential are for 0.7V.


circuit diagram:









Common Collector Configuration

the configuration of a transistor circuit in which collector is grounded or made common is called common collector configuration.

Properties:

the common collector configuration has very high input resistance 750 and flow outer output residens resistance 2 5 k ohm. due to high input resistance and low output resistant to this circuit is used for impedance matching.
in common collector circuit input current is best current and output current is the emitter current the ratio of change in emitter current IE

Formula;

r=IE/IB.

Circuit diagram:




input loop:

the input loop of common emitter configuration contain emitter diode full stop it is forward-based with the the VBB.
Apply Kirchhoff voltage rule.

Formula;

VBB=IBRB+VBE
IB=VBB-VBE/RB

Output loop:

the output loop contain collector diode RC as a load resistance it is reverse based.
apply Kirchoff  rule.

Formula;

VCE=VCC-ICRC

Biasing with the single voltage rule:

the +VBB at and the base makes input loop forward biased collector means output in reverse base.
apply Kirchhoff rule

Formula;

(+VCC)+(-IBRB)+(-VBE)=0
IB=VCC-VBE/RB