5
Application Examples
114
Keysight U1401B User’s and Service Guide
Determining transistor h
fe
For NPN-type BJT
1
Turn the rotary switch to the
/
position.
2
Connect the base to the positive output terminal.
3
Connect the emitter to the negative output terminal and the negative terminal
of a DC power supply (which supplies the required V
DD
).
4
Connect the collector to the negative input terminal.
5
Connect the positive terminal of the DC power supply to the positive input
terminal through a resistor.
6
Output a constant current of +1.000 mA (this is I
B
).
7
Read the measured current value (this is I
C
).
For PNP-type BJT
1
Turn the rotary switch to the
/
position.
2
Connect the base to the positive output terminal.
3
Connect the collector to the negative output terminal and the positive terminal
of a DC power supply (which supplies the required V
DD
).
4
Connect the emitter to the negative input terminal.
5
Connect the negative terminal of the DC power supply to the positive input
terminal through a resistor.
6
Output a constant current of -0.500 mA (this is I
B
).
7
Read the measured current value (this is I
C
).
The transistor h
fe
is calculated as the ratio of I
C
over I
B
.
NOTE
If you wish to obtain the correct results, please adjust the values of V
DD
and I
B
according to the conditions specified by the transistor manufacturer.