Programming instructions
BJT (NPN & PNP)
National Instruments Corporation 4-3 Multisim Component Reference Guide
where:
V
T
= thermal voltage = 0.0258
V
A
= forward early voltage
The model parameter
β
f
is equivalent to β
DC
in the DC case and β
AC
in the AC case
.
Other symbols used in these equations are defined in “BJT Model Parameters and Defaults.”
4.1.2 Time-Domain Model
The BJT time-domain model takes into account the parasitic emitter, base and collector
resistances, and also the junction, diffusion, and substrate capacitances. The capacitors in the
I
I
K
V
V
I
I
K
V
V
III
II
V
V
II
V
V
CE
S
qb
BE
CC
S
qb
BC
CT CE CC
BE S
BE
BC S
BC
=
−
=
−
=−
=
−
=
−
exp
exp
exp
exp
Τ
Τ
Τ
Τ
1
1
1
1
1
1
ComponentRef.book Page 3 Thursday, December 7, 2006 10:12 AM