Ac+Dc Voltage Measurement

TM 11-6625-444-14-2

h. Observe the display. It will indicate the

g. Push the POWER switch to the ON posi-

measured true rms ac voltage.

tion.

Figure 3-5. Average, Rms, and Peak Voltage Relationship of a Sine Wave

NOTE

b. Connect the test leads to the HI and LO lN-

PUT terminals, the red test lead to the HI termin-

al and the black test lead to the LO terminal.

The voltmeter will measure the rms

value of a sine wave including the

harmonics. It will respond to the

c. Push the AC+DC VOLTS switch to the in

rms value regardless of the phase

position.

of the input signal components. Fig-

ure 3-5 shows the sine wave rela-

tionship of average, rms and peak

NOTE

value.

If a guarded measurement is not nec-

essary, leave the GUARD switch in the

3-9. Ac+Dc Voltage Measurement

NORM position. For guarded measure-

ments push the switch in to the EXT

The voltmeter is capable of making measure-

position. See para 3-3.

ments of an ac rms voltage superimposed on a

dc level. Being a true rms voltmeter, it responds

to the heating factor of the composite waveform

d. Push the FILTER switch in to the LP/10 kHz

as given by:

position if the frequency of signals to be mea-

sured is known to be lower than 10 kHz. For

f r e q u e n c i e s higher than 10 kHz, leave the

FILTER switch in the out position.

Refer to figure 3-6 for illustrations of the ef-

e. For frequencies lower than 40 Hz, push the

feet of a dc offset voltage on the rms value of a

SLOW RESPONSE switch to the in position to a-

10 V peak-to-peak square wave.

For frequencies

chieve specified accuracies.

higher than 40 Hz, leave the switch in the out

position to obtain fastest readings.

a. Set the controls as indicated in para 3-5.b.