Table of Contents
Advertisement
Applications
3.3.1 Current gain checks
The dc current gain of a general purpose transistor can be
checked by configuring the transistor as a common emitter
amplifier. Figure 3-5 shows which crosspoints to close to
configure the amplifier circuit. In this circuit, gain is calcu-
lated by dividing collector current (measured by the Model
Measure
V or I
Source
V
Source
I
Figure 3-5
Transistor current gain checks
3-6
2000
A
I
B
±
224
I
E
I
C
Gain =
I
B
Equivalent Circuit
Volts HI
2 0 0 0 M U L T I M E T E R
Volts LO
Model 2000
Amps HI
Amps LO
Output
Common
Model 230
Model 224
2000) by base current (sourced by the Model 224). A profile
of the transistor operating characteristics can be obtained by
measuring the collector current over a specified voltage
range (V) for different base bias currents. For example, Fig-
ure 3-6 shows the characteristics of a typical NPN silicon
transistor at base bias currents (I) of 20µA, 40µA, 60µA and
80µA.
I
C
230
V
CE
H
G H
G H
1
2
H
A
L
H
B
L
C
H
L
D
H
L
E
H
L
F
H
L
G
H
L
HI
H
H
LO
L
Model 7077
G H
G
3
4
Advertisement
Table of Contents
Troubleshooting
