Amprobe HD160C Digital-Multimeter - Manual (Page 12)

6
Measuring AC Voltage - True rms (See Figure 2)
1. Set the Function Switch to �.
2. If RANGE is displayed, press the RANGE button to enable auto ranging.
3. Connect the test leads: Red to Temp VΩHz, Black to COM
4. Connect the test leads to the circuit test points.
5. Read the display, and, if necessary, correct any overload (OL) conditions.
True rms AC Measurements
Model HD160C is an ac-coupled True rms measuring meter. It measures the True rms value
of distorted AC voltage or current signals. The Crest Factor handling capability is shown in
Table 1. The Crest Factor is the Peak Voltage divided by the rms voltage.
5.0
4.0
3.0
2.5
1.0
2%
0%
5%
4%
3%
100% 80 60 40 20 0
Wave form,Crest Factor Additional correction from 1.5 to 5.0
Input RMS, Percentage of Full-Scale
Table 1 - Crest Factor Handling Capability
Note: To accurately measure a DC voltage with an AC component, measure the AC
component first with selector switch set to �. Note the measurement and range used.
Switch to �, activate Range Lock (see Button Functions later in this manual) and select a
range equal to or higher then the � range used previously. Note the measurement. The
result is the measured AC Voltage on top of the measured DC component. (Max input is
1500 V dc or 1000 V ac).