Keithley 2520, Service Manual, Page: 43 / 137

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-13
5. Select IL, then press ENTER. The instrument will prompt for the resistor:
RES VALUE: +15.000
Use ,
䊳
, , , ENTER or EXIT.
Table 2-5
Current source calibration values
Current source range Calibration resistor
500mA 10 to 15
Ω
5A 1.2 to 1.6
Ω
6. Enter the measured value of the 10 to 15
Ω
resistor, then press ENTER. The unit
displays the following:
IL-CAL
Connect Calibration Resistor to
䊳
Pulse Sense and Pulse Source
7. Connect the 10 to 15
Ω
resistor to the Model 2520 testhead VOLTAGE SENSE and
CURRENT OUTPUT jacks, as shown in Figure 2-3 .
8. Press ENTER to complete calibration of the present range.
9. Press EXIT to return to normal display.
10. Press LASER I
L
, then EDIT, then use the RANGE key to select the 5A current
range.
11. Press LASER V
L
, then use the RANGE key to make sure the 10V range is
selected.
12. Disconnect the 10 to 15
Ω
resistor, then connect the 1.2 to 1.6
Ω
resistor in its place
( Figure 2-3 ).
13. Repeat steps 3 to 9 for the 5A range using the 1.2 to 1.6¾ resistor instead of the
10 to 15¾ resistor.
Figure 2-3
Current source calibration connections
CURRENT
OUTPUT
VOLTAGE
SENSE
CAT I
DETECTOR 1 DETECTOR 2
BIAS
CURRENT
INPUT
ISOLATION FROM EARTH: 10V MAX.
HI
HI
LO
LO
!
!
Model 2520 Testhead
CURRENT OUTPUT HI
CURRENT OUTPUT LO
10 to 15
Ω
Resistor
(500mA Range)
1.2 to 1.6
Ω
Resistor
(5A Range)
VOLTAGE
SENSE HI
VOLTAGE
SENSE LO