Shields And Guarding; Figure 2-11 Basic Connections To Dut - Keithley 6220 Reference Manual

2-16 Output Connections Model 6220/6221 Reference Manual
Figure 2-11
Basic connections to DUT
A) Inner shield connected to Output Low B) Inner shield connected to Cable Guard

Shields and guarding

Noise shield connections
Figure 2-12 shows typical noise shielding for the two triax connector
configurations. A noise shield is used to prevent unwanted signals from being
induced into the test circuit. A test current below 1μA may benefit from effective
shielding. Typically, the metal noise shield surrounds the DUT and is connected to
Output Low.
Safety shield connections
A safety shield must be used whenever hazardous voltages (>30Vrms, 42Vpeak)
will be present. The metal safety shield must completely surround DUT test
circuitry and must be connected to a known Safety Earth Ground and Chassis
(see Figure 2-13). Use #18AWG wire or larger for connection to safety Earth
Ground and Chassis.
Return to Section 2 topics
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