B&K Precision 5491B - Manual - Manual (Page 24)

24
Note: Source current flows from the to COM terminals
Figure 3-3 Resistance Measurements
3.5 Measuring Frequency and Period
Frequency measurement range: 5 Hz to more than 1 MHz.
Period measurement range: 0.2 s to less than 1 μs.
Input signal range: 200 mV AC to 750V AC.
The instrument uses the volts input terminals to measure frequency. The AC voltage range can be
changed with the RANGE and keys. However, the signal voltage must be greater than
10% of the full-scale range.
3.5.1 Trigger Level and Measurement Errors
The multimeter uses a technique which maintains a constant resolution for any input frequency to
measure frequency and period. The gate time is always a multiple of the measured signal period rather
than a fixed time. The error will be no more than +/-1 from the total gate counts, which assures an
equivalent accuracy over the whole frequency range.
3.5.2 Gate Time
Gate time is the amount of time the meter uses to sample frequency or period readings. The
measurement speed rate and the measuring frequency change the gate time.
3.5.3 Connections
Assuming the multimeter is under factory default conditions, the basic procedure for measuring
frequency and period is as follows:
1. Connect test leads to and COM terminals.
2. Select frequency or period measurement functions by pressing or →
3. Connect test leads to the source as shown in Figure 3-4:
CAUTION: Do not exceed 1000 V peak between and COM, or instrument may be
FREQ FREQ