Transistor Beta (β) Calculation at VCE = 10V
Collector-Emitter Voltage (VCE) in Volts
Collector Current (IC) in mA
0
5
10
15
20
0
2
4
6
8
VCE = 10V
IB = 20μA, IC = 3.0mA
IB = 30μA, IC = 4.5mA
Target: IC = 4.0mA
AC Current Gain (βac) Calculation
βac represents the small-signal current gain and is calculated as:
βac = ΔIC / ΔIB (at constant VCE)
From the output characteristics at VCE = 10V:
ΔIB = IB2 - IB1 = 30μA - 20μA = 10μA
ΔIC = IC2 - IC1 = 4.5mA - 3.0mA = 1.5mA
Therefore:
βac = 1.5mA / 10μA = 150
AC Current Gain: βac = 150
DC Current Gain (βdc) Calculation
βdc represents the DC current gain and is calculated as:
βdc = IC / IB
For the first operating point:
IC = 4.5mA, IB = 30μA
βdc = 4.5mA / 30μA = 150
For the second operating point:
IC = 3.0mA, IB = 20μA
βdc = 3.0mA / 20μA = 150
The average DC current gain is:
βdc = (150 + 150) / 2 = 150
DC Current Gain: βdc = 150
