Associated Research HypotULTRA 7800, Operation And Service Manual

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TEST TYPE PARAMETER VALUE
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4.12.3 Additional Parameter Notes and Functions
Real Current
The AC Real Current function allows you to monitor only the real portion of the
leakage current and ignore any reactive components due to capacitance in the device
under test. It is important to recognize that the total current is the vector sum of the
reactive and real current, not the direct addition of the two components. As in a right
triangle, the total current is the square root of the sum of the squares of the real and
reactive currents.
Since the real component is usually much smaller than the reactive current, a doubling
of the real current increases the total current by only a small amount. Unless the two
components are separated, a doubling of the real leakage current can go virtually
undetected by a total current measurement.
Because Real Current is installed in HypotULTRA, additional parameter selections are
added to the ACW test parameters. The additional test parameters are HI-Limit R
(Real Current Maximum limit), LO-Limit R(Real Current Minimum Limit) and Display.
The standard total current limits have a “T” next to them indicating total current.
The AC Real Current function allows the operator to view both real and total current
simultaneously. The Display parameter allows you to select which meter will display
the real and total current. When the display parameter is set for Total, the large
current meter will display the total current and the small current meter below the
memory location will display the real current. The opposite is true when you set the
display for Real.
Ramp-HI
The Ramp-HI function is active during the Ramp period only. Ramp-HI will allow
current higher than the normal HI-Limit current setting of the DC Withstand Voltage
test to avoid false failure due to charging current.
Charge
–LO
Use the Charge-LO function to check if the cables are connected properly at the
beginning of a test. A capacitive DUT will draw charging current on the DC Withstand
test when the Output is activated. If the charging current is lower than the setting, the