Keithley 6487 Reference Manual

Model 6487 Reference Manual Measurement Concepts and Connections 2-3
Maximum input levels
The maximum input levels to the Model 6487 are summarized in Figure 2-2.
t^okfkd The maximum safe voltage between the voltage source or ammeter
common and chassis ground (common mode voltage) is 505V peak.
Exceeding this voltage can create a shock hazard.
`^rqflk Maximum continuous input voltage is 505V peak.
Figure 2-2
Maximum input levels
Low-noise input cables
When making precision measurements, you should always use low-noise cables for
INPUT connections. The following low-noise cables are recommended for use with the
Model 6487:
Model 237-ALG-2 Triax Cable — This 2m (6.6 ft) low-noise triax cable terminated with
a 3-slot male triax connector on one end and 3 alligator clips on the other end.
Models 7078-TRX-3, 7078-TRX-10, and 7078-TRX-20 Triax Cables — These are low-
noise triax cables terminated at both ends with 3-slot male triax connectors. The -3 model
is 3 ft. (0.9m) in length, the -10 model is 10 ft. (3m) in length, and the -20 model is 20 ft.
(6m) in length.
klqb As a general rule, always use the shortest possible cable for measurements.
Input HI
Input LO
505V Peak
Chassis Ground
Max Continuous
Input = 505V Peak
505V Peak

Keithley 6487 Specifications

General

Type	Picoammeter/Voltage Source
Current Measurement Range	20 fA to 20 mA
Interfaces	GPIB, RS-232
Voltage Burden	< 200 µV
Input Impedance	>10^14 Ω
Power	100 V / 120 V / 220 V / 240 V
Basic Current Measurement Accuracy	0.4%