Ebers Moll Model h parameter r parameter z parameter Forward Mode , Reverse Mode And Normal Mode 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