Electro-Metrics EM-2115, Instruction Manual

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EM-2115 APPENDIX E ACCESSORY DATA
(EM2115E-12)
E-3.1 EM-6981 Current Probe
E-3.1.1 EM-6981 Specifications
a. Electrical
Frequency Range (Calibrated): 9 kHz to 110 MHz.
Calibration Factor Chart furnished with each antenna. Refer to Figure E.7 for
typical transfer impedance factor chart.
Impedance: 50

, nominal.
Output Connector: TNC, female.
b. Mechanical
Outside Diameter: 73 mm (2.875").
Thickness: 32 mm (1.25").
Weight: 454 g (1 lb).
E-3.1.2 EM-6981 Description
The EM-6981 Current Probe enables a conventional voltmeter, oscilloscope, calibrated
receiver (e.g., EM-2115), or other electronic instrumentation to rapidly measure current accurate-
ly from 9 kHz to 110 MHz. The response of the probe is proportional both to signal frequency
and conducted signal current.
The EM-6981 Current Probe is an instrument type transformer that utilizes the conductor
under test as a single turn primary winding with the probe, clamped around the conductor, as the
secondary. The current probe is capable of placement around conductors with diameters up to
and including 25.4 mm (one-inch).
In order to minimize the effects of stray fields, the outside case of the probe is specially
constructed to form an electrostatic shield. The EM-6981 has a ferrous-type core that is designed
to negate any saturating effects and thus prevent erroneous measurements with primary currents
up to 300 amperes from DC to 400 Hz.
Intermodulation effects on current probe output are also negligible for primary currents
up to but not in excess of 300 amperes from DC to 400 Hz.
The EM-6981 is connected to the EM-2115 via a 50

coaxial cable.
E-3.1.3 EM-6981 Applications