Kikusui TOS9200, Operation Manual

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3-28 Basic Operations TOS9200/9201
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LO W
In the LO W mode, the current which fl o ws through the LO W terminal by insulation
resistance of the test leadwire and jigs is included in the measurements, as sho wn in
Fig. 3-8 (A) and (B). Ho we v er , the ammeter is protected from short-circuiting,
thereby ensuring safe testing re g ardless of whether the DUT is grounded. F or this
reason, it is recommended that LO W be set in ordinary tests.
(A) DUT g rounded
(B) DUT not g rounded
Fig.3-8 Selecting LO W
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GU ARD
• If it is not kno wn whether the DUT or jig is g rounded, ne v er select GU ARD .
If GU ARD is selected while the DUT is g rounded, the ammeter will be
shor t-circuited, thereb y disab ling measurement and posing a g r a v e dan -
ger . See Fig. 3-9 (B).
• If GU ARD is selected, do not connect this tester to an y measur ing instr u -
ments or other de vices that in v olv e single-side g rounding, such as
Kikusui’ s high-v oltage digital v oltmeter 149-10A and current calibr ator
T OS1200. Otherwise , the ammeter will be shor t-circuited. See Fig. 3-9
(A).
Insulation
resistance of test
lead wire and jigs
Setting to LOW
Ammeter
TOS9201
HIGH VOLTAGE terminal
LOW
terminal
D
U
T
Insulation
resistance of test
lead wire and jigs
Setting to LOW
Ammeter
TOS9201
HIGH VOLTAGE terminal
LOW
terminal
D
U
T
WARNING