Iso-Tech IDM 103N Instruction Manual page 14

Note – When measuring voltage, the Meter acts like a 10MΩ
impedance in parallel with the circuit under test. This loading
effect of the 10MΩof the Meter can cause measurement
errors, loading efffect error, Especially in high impedance cir-
cuits.
For example : A 1.1M impedance circuit will cause a –10%
measuring error. The error percentage of the loading effect
of the Meter is expressed as following :
- Zcircuit
x
%
100
Zcircuit + 10MΩ
The non-zero display reading is normal when the meter test
leads are open, which will not affect actural measurement
accuracy. The Meter will show zero or close to reading when
the test leads are shorted. In reading AC voltage or current,
reading-settling time increases to several seconds at the low
end of AC voltage and current ranges in rms models.
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