Extech Instruments 470 - Manual (Page 11)

V5.0 5/04 11
AC CURRENT MEASUREMENTS
CAUTION: Do not make current measurements on the 20A
scale for longer than 30 seconds. Exceeding 30 seconds may
cause damage to the meter and/or the test leads.
1. Insert the black test lead banana plug into the negative COM
jack.
2. For current measurements up to 4000µA AC, set the function
switch to the yellow µA position and insert the red test lead
banana plug into the µA/mA jack.
3. For current measurements up to 400mA AC, set the function
switch to the yellow mA position and insert the red test lead
banana plug into the µA/mA jack.
4. For current measurements up to 20A AC, set the function
switch to the yellow A range and insert the red test lead
banana plug into the A jack.
5. Press the SELECT button to
indicate “AC” on the display.
6. Remove power from the
circuit under test, then open
up the circuit at the point
where you wish to measure
current.
7. Touch the black test probe tip
to the neutral side of the
circuit.
Touch the red test probe tip to
the “hot” side of the circuit.
8. Apply power to the circuit.
9. Read the current in the
display.