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5-3. Line Frequency Measurements
Use of the attenuator, low pass filter, and/or x10 probe is advisable when measuring
line frequency because the high amplitude signal and noise can cause wrong counting.
WARNING
USE CAUTION IN MEASURING THE LINE FREQUENCY OF AN AC OUTLET.
USING THE PROBE TIP ONLY, MEASURE BOTH SIDES OF THE LINE. THE
GROUND SIDE WILL GIVE A ZERO READING AND THE HOT SIDE WILL PROVIDE
THE DESIRED MEASUREMENT. DO NOT USE THE "GROUND "LEAD OF THE
PROBE. REMEMBER THAT THE CHASSIS OF THE COUNTER AND THE
“GROUND” LEAD OF THE PROBE ARE ALREADY AT EARTH GROUND (VIA THE
3-WIRE POWER CORD OF THE INSTRUMENT). TOUCHING THE
“GROUND "LEAD TO THE 'HOT" SIDE OF THE LINE WOULD PLACE A DIRECT
SHORT ON THE POWER LINE THROUGH THE PROBE CABLE, RESULTING IN
POSSIBLE INJURY AND DAMAGE TO THE PROBE CABLE.
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