Difference Amplifier Calculator

R1 (KΩ) 
R2 (KΩ)
RC(Collector resistor) (KΩ) 
RE(Emitter resistor) (KΩ) 
VP (Supply Voltage) (V)
Beta (DC Current Gain)
VBE (Base to emitter drop) Base-emitter voltage drop (V)
RsSource Resistance: (Ω)
RL(Load resistor) (Ω) 
fT(Current Gain BW Product): Current Gain Bandwidth (MHz)
CCB(Cu Collector-Base Cap.): Capacitance between collector and base (pF)
CBE(Cπ, Base-Emitter Cap.): Capacitor between base and emitter (optional) (pF)

VC(Collector Voltage) Collector Voltage (V) 
VE(Emitter Voltage) (V) 
VB (Base Voltage) (V) 
IE(Emitter Voltage) (mA) 
IC(Collector Voltage) Collector Voltage (mA) 
IB (Base Voltage) (mA) 
gm (Transconductance)
rπ (Input Resistance of BJT at low freq) Transistor input impedance, low frequency (Ω)
re  (Ω)
RIN (Input Resistance of Amp)Amplifier Input Impedance (KΩ)
A (Amplifier Voltage Gain) Amplifier voltage gain
fP1 (MHz)
fP2 (MHz)

VB=  VP*R2/(R1+R2)

VE= VB-VBE

IE=VE/RE

Alpha= Beta/(Beta+1);

IC= Alpha*IE

VC= VP -  IC*RC/2

IB=IC/Beta

 

gm = Ic/25mA

re= Alpha/gm

rπ= Beta/gm

A=Alpha* rπ*RC/(Rs+2*rπ)/re

fP1=1/(2*π*(Rs||2*rπ)*(CBE/2+CBC))

fP2=1/(2*π*RC*CBC)

 

fT= gm/(2π*(CBE+CBC))

The lower pole is dominate: 

 

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