Fluke 279FC User Manual - Page 37

Frequency Measurements A frequency measurement is a count of the number of times an ac voltage or current signal passes through a threshold point each second. The Multimeter auto ranges to one of these frequency ranges: • 2.00 Hz to 99.99 Hz • 100.0 Hz to 999.9 Hz True-rms Thermal Multimeter Basic Measurements Hints for frequency measurements: • If a measurement shows 0 Hz or is not stable, the input signal can be below or near a trigger level. A lower range increases the sensitivity of the Multimeter and can usually repair these problems. • An input signal with distortion can cause a frequency measurement to be higher than usual. The distortion can cause the frequency counter to sense multiple triggers. A higher voltage range decreases the input sensitivity and can correct this problem. In general, the lowest frequency is the correct one. Be sure that you use the correct accessory for the measurement type. See Figure 12. 27