20 Clamp-on Meter Models 501 and 5034.8 Frequency Measurement UsingCurrent InputNOTE: Remove the test leads before measuring current• Turn the rotary range switch to the range.• Press the lever to open the jaws.• Clamp the jaws around the conductor to be mea-sured.WARNING: Do not use both voltage and cur-rent inputs at the same time when measuringfrequency. This may be dangerous. Errone-ous readings will occur if both inputs are usedat the same time.