Figure 3-3. Common Mode Signal Configuration

TM 11-6625-444-14-2

shunting these currents away at the source.

(3) Operating the voltmeter in the pres-

ence of high level, radiated noise such as stray

fields at powerline frequencies.

When making off-ground (guarded)

b. For normal voltage measurements the

measurements the internal guard

GUARD terminal may be connected directly to

shield may be at a dangerous po-

the LO input terminal. The GUARD switch is

tential to ±300 volts with respect

provided f o r this convenience.

to case ground. Exercise proper

shows the affect of measurements taken in a

personnel hazard precautions

normal (NORM) condition while figure 3-4 illus-

when connecting and disconnect-

trates how a guarded (EXT) measurement mini-

ing test leads.

mizes the affects of common mode noise by

Figure 3-3. Common Mode Signal Configuration