Keithley 220 Instruction Manual page 24

MODEL 220
REAR PANEL
MODEL 192
FRONT PANEL
Figure 3-l. lOOmA to 1mA RangeVerifIcation
Table 3-2. 100mA to 1 mA Verlflcatlon
Model 192"
Model 220 Model 220 Model 102 Allowable Readlng
Range output Range (16% to 28°C)
lOOmA 50.00mA" 2OVdC 5.0090 to 4.9910
IOmA lO.OOOmA 2Vdc
1.00132 to 0.99666
1mA 1 .OOOOmA 2Vdc 0.10013 to 0.09967
'Includes test equipment l&mnc86.
"Apply momentarily to prevent the resistOr from overheating.
3.5.2 lOOvA and 10vA RangeVerIficatIon
1. Replace the 1OOQ resistor in Figure 3-1 with the lOOka
resistor specified in Table 3-1.
2. Select the 20VDC range on the Model 192.
a. Program the Model 220 to output +OO.OO-6. Verify
that the reading on the Model 192 does not exceed
+lOmV.
b. Program the Model 220 to output +O.OOO-6. Verify
that the reading on the Model 192 does not exceed
+ImV.
3. Program the Model 220 to output +100.00-6 amps with
20V compliance.
4. Verify the reading on the Model 192 to be between
10.0120 and 9.9660.
5. Select the 2VDC range on the Model 192.
6. Program the Model 220 to output +lO.OOO-6 amps with
20V compliance.
7. Verify the reading on the Model 192 to be between
1.00122 and 0.09676.
6. Repeat steps 2 through 7 with negative output current.
3.6.3 1 pA and 1 OOnA Range Verlflcatlon
1. Construct the test fixture shown in Figure 3-2 using the
1 OMfi resistor as R.
2. Measure the lOMa resistor with the Guildline 9520 and
note the value.
3. Set up the circuit shown in Figure 3-3.
4. Set the Model 192 to the 20VDC range.
5. The GUARD of the Model 220 may input an offset of
*l mV to the Model 192. To cancel this offset, proceed as
follows:
A. Program the Model 220 to output *O.OOOO-6A.
i3. Short the 1 OMQ resistor.
C. Zero the display of the Modal 192 by pressing the
ZERO button.
D. Remove the short from the 10Mn rssistor.
6. Program the Model 220 to output +l.OOOO-6A with a 20V
compliance.
3-2