Keithley 486

SECTION2
Geffina Sfarfed
Equivalent Circuit
Guard
Disabled
2igure 2-5.
Connections to Measure Current
is properly connected to the test fixhm (see
Figure Z-6). With proper use of Interlock, the
V-Source will not apply voltage to the test
fixture when the lid of the test fix&m is
OPm
WAlZNlNG
To provide protection from shock hazards,
the test fixture chassis must be properly con-
nected to a safety earth ground. A grounding
wire (18 AWG or larger) must be attached se-
curely to the test fixture at a sczew temdnal
designed for safety grounding. The other
end of the ground wire must then be at-
tached to a known safety earth ground.
5. Set the V-Source of the Model 487 to the desired volt-
age level as follows:
A. Select the V-Source range. To select the 50V
range, keep pressing and releasing the, key un-
til the 3JV mnge is displayed (i.e. OV on the 5OV
range is displayed as “OO.OWJ”). To select the
500V range, keep pressing and releasing the 4
key until the 5CW range is displayed (i.e. OV on
the SOOV range is displayed as “OOO.OOV”).
B. Use the 4 and b keys to position the cursor
Washing digit, on the digit to be modified.
C. Use the rotary knob to increase or decrease the
voltage level from the selected digit.
Note: As a general rule, the V-Source should be
set as high as possible to optimize V/I Ohms
measurement accuracy.
4. On the Model 487, press SHIFT and then CORRECT
to perform zero correction. This will cancel any inter-
6. On the Model 487, press ZERO CHECK to disable
nal offsets.
zero check, and press OPERATE to apply the pm-
gr-ed voltage to the test fixture. The resistance of
2-7