Multimeter  (220-0179)           Operation            Faxback Doc. # 6267

Measuring DC/AC Voltages

Warning:  Never touch a hot wire (usually red, black, or blue, in AC
          wiring circuits).  If you do so and then touch the other probe
          connected to the multimeter, you could receive an electric
          shock.

Cautions: 

Do not operate the multimeter until you correctly install the
batteries and close the battery compartment cover.

The maximum voltage input limit is 400V DC and AC, OL blinks on the
display and the buzzer sounds when you connect the multimeter to a
voltage above this limit.  If you see or hear these indications,
immediately disconnect the test probes from the circuit under measurement
or you might damage your multimeter.

Always remove power from the circuit to be measured before you connect
the test leads to a high voltage point, then follow these steps to
measure DC or AC voltages.

1.  Set the function switch to DCV or ACV.  AC appears on the left bottom
    of the display when the function switch is set to ACV.

    Note: The buzzer automatically turns on when you turn on the
    multimeter.

2.  Connect the test leads' probes to the circuit to be tested.

3.  After connecting the test leads to the circuit, reapply power to read
    the displayed measurement.  The range automatically shifts to the one
    that gives the best reading.

4.  Remove power again before you disconnect the test leads.

Note:  When the meter is in the AC/DC mV range and the test leads are
       not connected to an actual circuit, the meter might display a
       wandering effect (phantom reading).  This is normal and is not
       a problem.  The display shows a proper measurement when the
       test leads are connected to a circuit.

Measuring AC Voltage Riding on a DC Source Bias

Caution:  Never attempt to measure any voltage more than 30V AC on a DC
          source bias.  Doing so might damage your multimeter.  The
          multimeter cannot directly measure an AC voltage superimposed
          on a DC voltage source bias.  If you know the approximate
          voltage of the device to be measured and it is under 30V DC/AC,
          you can measure the voltage by following these steps.

1.  Set The function switch to ACV.

2.  Connect the negative (-) test lead to the circuit's neutral or ground
    lead.

3.  Connect a 0.1 microfarad/100V mylar capacitor in series with the
    positive terminal of the voltage source and the (+) test lead.

Voltage Measurement Hints

When measuring DC voltages, the minus sign (-) appears if you connect
the black lead to a point in the circuit that has a higher voltage
potential than where you connect the red lead.

When you use the multimeter to probe for a voltage in a high-voltage
circuit, do not try to position both test probes at once.  Instead, clamp
one test probe to the circuit's neutral or ground lead (usually a bare,
green, or white lead, in AC wiring circuits) using insulated Slip-On
Alligator Clips (Cat. No. 270-354). Then probe for voltages with the
other probe.  This helps prevent you from accidentally touching a hot
wire, since you only need to concentrate on one test probe.

(RLR/smc-05/16/94)