Keithley 2000, Руководство пользователя, Страница: 36 / 280

Measuring voltage
The Model 2000 can make DCV measurements from 0.1µV to 1000V and ACV measure-
ments from 0.1µV to 750V RMS, 1000V peak.
Connections
Assuming factory default conditions, the basic procedure is as follows:
1. Connect test leads to the INPUT HI and LO terminals. Either the front or rear inputs can
be used; place the INPUTS button in the appropriate position.
2. Select the measurement function by pressing DCV or ACV.
3. Pressing AUTO toggles autoranging. Notice the AUTO annunciator is displayed with
autoranging. If you want manual ranging, use the RANGE
▲
and
▼
keys to select a
measurement range consistent with the expected voltage.
4. Connect test leads to the source as shown in Figure 2-4.
CAUTION Do not apply more than 1000V peak to the input or instrument damage may
occur. The voltage limit is subject to the 8
×
10
7
V•Hz product.
5. Observe the display. If the “OVERFLOW” message is displayed, select a higher range
until an o normal reading is displayed (or press AUTO for autoranging). Use the lowest
possible range for the best resolution.
6. Take readings from the display.
Crest factor
AC voltage and current accuracies are affected by the crest factor of the waveform, the ratio
of the peak value to the RMS value. Table 2-3 lists the fundamental frequencies at which the cor-
responding crest factor must be taken into account for accuracy calculations.
Table 2-3
Crest factor limitations
Crest factor Fundamental frequency
2
3
4-5 50kHz
3kHz
1kHz
2-18 Basic Measurements