N2782/3B Current Probes
N2780/1/2/3B User’s Guide
9
Current Direction Indication
Align the sensor so that the current direction indication corresponds to the
direction of current flow through the conductor to be measured.
LOCK/UNLOCK Indication
Indicates if the sensor head is closed or open.
Demagnetizing Switch (DEMAG)
This demagnetizes the core if it has been magnetized by switching the power on
and off, or by an excessive input. Always carry out demagnetizing before
measurement. The demagnetizing process takes about one second. During
demagnetizing, a demagnetizing waveform is output.
BNC Output Connector
Connect to the oscilloscope’s BNC input connector. Turn the collar until it clicks,
and check that it is locked securely.
NOTE
The output of the current probe is terminated internally. You must select
the input impedance of the oscilloscope to be 1 M
Ω
to make accurate
measurements. If the oscilloscope you are using does not have a 1 M
Ω
input impedance setting you can purchase the E2697A 50
Ω
to 1 M
Ω
adapter. The output resistance of probes is approximately 25
Ω
(30A/50
MHz: N2782B-FG), 7
Ω
(150A/10 MHz: N2781B-FG), 41
Ω
(500A/2 MHz:
N2780B-FG), 25
Ω
(30A/100MHz: N2783B-FG).
Power Supply Cable
Connect this to the N2779A power supply receptacle to supply power to the
sensor terminator.
Zero Adjustment Dial (ZERO ADJ)
Use the zero adjustment dial to correct for the effect of a voltage offset or
temperature drift on the unit. The probe should be always be zeroed after
demagnetization.
