The document explains the Ebers-Moll model for Bipolar Junction Transistors (BJTs), which includes two interconnected diodes and current sources to describe their behavior. It outlines equations for forward and reverse mode operations, detailing how currents at the transistor's terminals are influenced by applied voltages and each other. Key parameters such as the common collector current gain and thermal voltage are also introduced in the context of the model's operation.

1. Electronics

2. *Ebers Moll Model
*h parameter
*r parameter
*z parameter

4. Ebers MOLL Model For BJT
• It consist of two diode (p-n junction) which
are connected to back to back and the base is
common to both diodes
• In addition we have the two current sources
these current sources gives the coupling
between the two junctions

6. • These diode are not in insolation but are
interdependent it means that the total current
flowing in one diode it is influenced by the
other
• When the diode are in insolation then they
are characterized by the normal diode
equation

7. IF = forward current
IR = reverse current
IES = reverse saturation current for base emitter junction
ICS = reverse saturation current for base collector junction
VT = thermal voltage
VBE = potential difference between the base and emitter
junction
VBC = potential difference between the base and collector
junction

8. • When two junctions are combined to form a
transistor the base region is shared by both
• The idea of this model is that if u know about
applied voltages between junction we should
be able to evaluate the different currents
• Now we find the 3 terminals current

10. Forward mode operation :
• In the forward mode of operation αF
of the emittor current reaches the collector
This means that diode current passing through
the base-emitter junction contributes to the
current flowing through base-collector
junction. αF (0.98-0.99)

11. Forward mode operation:
IC=αFIF
IE=IF
IB=(1-αF)IF

12. Reverse mode operation :
In this case αR times the
collector current contributes
to the collector current αR
(0.1 to 0.5) (common
collector current gain )

13. Reverse mode operation equations:
VBE=0
IF=0
IE= -αRIR
IC=-IR
IE=IB+IC
IB=IE-IC
IR(1- αR)

14. Normal mode operation
equations :
VBE≠0
VBC≠0
Then Ic=αFIF-IR
IE=IF-αRIR
IB=(1-αF)IF+IR(I-αR)
These are the Ebers moll model
equation or terminal currents