Test Products International 275 - Manual (Page 17)

Measuring AC Amperage
CAUTION!
Do not attempt to make a current measurement with the
test leads. The 275 measures the current by clamping the
jaw around one conductor (wire). Clamping around more
than one wire will result in erroneous readings. Make sure
the temperature probe is NOT plugged in during this test.
Instrument set-up:
FUNC. BLACK RED MIN MAX
TEST LEAD TEST LEAD READING READING
NOT USED NOT USED 0.01A 400A
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Set rotary switch to function.
3. Clamp the jaws around one conductor of the circuit to
be measured. For best results, center the wire in the
jaw.
4. Reconnect power to circuit to be measured.
5. Read the current on the 275.
Optional Modes (See Other Features Section)
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measure-
ments
• P-H: Displays peak amperage.
17
16
Measuring Resistance
WARNING!
Do not attempt to make resistance measurements with circuit
energized. For best results, remove the resistor completely from
circuit before attempting to measure it. Make sure the tempera-
ture probe is NOT plugged in during this test.
NOTE:
To make accurate low ohm measurements, short the ends of the
test leads together and press the REL button to store the reading.
This will deduct the stored value from subsequent measurements
eliminating the test lead resistance from the reading.
Instrument set-up:
FUNC. BLACK RED MIN MAX
TEST LEAD TEST LEAD READING READING
Ω COM V/ Ω 0.1 Ω 40.00M Ω
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/
Ω
input jack.
4. Set the rotary switch to the
Ω
function.
5. Connect test leads to circuit to be measured.
6. Read the resistance value on the 275.
Optional Modes (See Other Features Section)
• D-H: Freezes the reading on the LCD.