# PyAMS  (the software under revision)

## BJT(NPN)

The equivalent of ideal BJT of NPN type

### Information

The BJT (npn) which is represented by The Ebers-Moll model,The equivalent of the transistor can be represented by three current sources Ibc, Ibe and Ict it is dependent on the voltage in the three nodes c, b and e:

### Parameters

NameDefaultDescription
Is1e.0-12Transport saturation current [A]
Vt0.025Voltage equivalent of temperature (kT/qn) [V]
NF1.0Forward current emission coefficient
NR1.0current emission coefficient
area1.0Area
BR1Ideal maximum reverse beta
BF460.0Ideal maximum forward beta

### PyAMS definition

```from PyAMS import Signal,explim
from math  import sqrt

class NPN:
def __init__(self,c,b,e):
#Signals
self.Vbe=Signal('in','voltage',b,e)
self.Vbc=Signal('in','voltage',b,c)
self.Ibc=Signal('out','current',b,c)
self.Ibe=Signal('out','current',b,e)
self.Ice=Signal('out','current',c,e)
#paramaters
self.NF=1.0           #Forward current emission coefficient
self.NR=1.0           #current emission coefficient
self.Is=1.0e-16       #Transport saturation current
self.area=1.0         #Area
self.BR=1             #Ideal maximum reverse beta
self.BF=460.0         #Ideal maximum forward beta
self.Vt=0.025         #Voltage equivalent of temperature

def analog(self):
Vt=self.Vt
Ibe=self.Is*(explim(self.Vbe/(self.NF*Vt))-1)
Ibc=self.Is*(explim(self.Vbc/(self.NR*Vt))-1)
Ict=Ibe-Ibc
self.Ibc+=Ibc/self.BR+(self.Vbc/1e+12)
self.Ibe+=Ibe/self.BF+(self.Vbe/1e+12)
self.Ice+=Ict

Documentation generated by PyAMS ```