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AC current measurement (Model 72-7765A only)
• The testing ranges are: 400μA, 4000μA, 40mA, 400mA, 4A and 10A
• To measure AC current, perform the following steps:
• Turn off the power and discharge all high-voltage capacitors of the circuit to be
measured.
• Insert the red test probe into the VΩmA or 10A terminal and the black test probe
into the COM terminal.
• Turn the range selector to μA/mA/A range.
• Press the SELECT button for switching DC measurement to AC measurement.
• Connect the red test probe to the positive electrode and the black test probe to the
negative electrode of the circuit in series.
• Turn on the circuit power. The measured value shows on the display.
Notes:
• If the current to be measured is unknown, use the maximum measurement range
(10A) and reduce the range step by step until a satisfactory reading is obtained.
(Do not adjust when connected to the circuit).
• When current measurement has been completed, disconnect the testing probes
from the circuit under test.
Resistance measurement (See Figure 5)
WARNING: To avoid damages to the meter or to the devices under test, disconnect
circuit power and discharge all the high-voltage capacitors before measuring resistance.
Model 72-7765A testing ranges: 400Ω, 4kΩ, 40kΩ, 400kΩ, 4MΩ and 40MΩ
Model 72-10420A testing ranges: 200Ω, 2000Ω, 20kΩ, 200kΩ and 20MΩ
Model 72-7770A testing ranges: 200Ω, 2000Ω, 20kΩ, 200kΩ, 20MΩand 200MΩ
To measure resistance, perform the following steps:
• Insert the red test probe into the VΩmA terminal and
the black test probe into the COM terminal.
• Turn the range selector to Ω range(s).
• Connect the test probes to the circuit in parallel.
• Read the testing result on the display.
Notes:
• The test probes can add 0.1Ω to 0.3Ω of error to
resistance measurement. To obtain precise reading
in low-resistance measurement, short-circuit the test
probes beforehand and record the reading obtained.
Subtract this value from the measured value to obtain the resistance of the circuit
under test.
• For high resistance measurement (>1MΩ), it normally takes several seconds to
obtain a stable reading.
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