UNI-T UT20B Operating Manual page 12

Note
l
If the value of voltage to be measured is unknown, use the maximum
measurement position (300V) and reduce the range step by step until a
satisfactory reading is obtained.
l
In each range, the Meter has an input impedance of approx. 0.5M . This loading
effect can cause measurement errors in high impedance circuits. If the circuit
impedance is less than or equal to 1k , the error is negligible (0.2% or less).
l
When AC voltage measurement has been completed, disconnect the connection
between the testing leads and the circuit under test.
Model UT20B: OPERATING MANUAL
Measurement Operation (2)
12