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SEFELEC1500M Instructions
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V1.06
8.2.
PRECAUTIONS TO OBSERVE DURING A MEASUREMENT:
To take a resistance measurement beyond a Teraohm, use an effective shielding connected to
the guard terminal (grey terminal on the front panel for a floating measurement or ground termi-
nal on the rear panel for a measurement with the guard connected to the ground). Erroneous
measurements due to the presence of parasitic leakage currents or to introductions of mains
fields are as such prevented.
The proximity of an operator bringing his hand close to the tested sample can distort the meas-
urement. Care should be taken not to wear nylon lab coats and to avoid insulating objects
which may create high static electricity fields which could affect the operation of the device at
very low levels of current. A measurement of 10 Teraohm under 10 volts corresponds to a
measurement of a current of 1 pA.
When measuring capacitive circuits (use the CABLE or CAPACITOR mode, chapter 7-4) never
take measurements by decreasing the voltage measurement at each test but always by in-
creasing it; the phenomena of hysteresis and polarisation presented by the dielectric would
distort the results. In this case the device will tend to indicate the maximum and will take a long
time to fall to the real value to be measured.
Never disconnect a capacitive sample without switching to DISCHARGE mode with the
STOP push-button and waiting for the time required for the capacitance of the sample to
discharge into the 2.2 kΩ resistor of the discharge circuit.
After connecting the component to be measured with the precautions described hereinabove
and selecting the required measuring parameters, return to the measuring screen hereinbelow: