FESP 5133 - Circular screened Coil

  • Schwarzbeck FESB5133 Loop Sensor  Antenna


The magnetic, handheld coil FESP 5133 was designed to generate defined magnetic field strength in the audio frequency range up to 100 kHz. The main application is immunity testing against magnetic fields according to e.g. (of professional studio equipment acc. to EN 55103), MIL-STD 461, VG 95377 part 13) and many others). Depending on the current source characteristics magnetic fields up to 1000 A/m can be generated for a short time.

The generated magnetic field strength is proportional to the coil current. Two different distance rings (50 mm and 100 mm separation) are supplied to ensure a well defined spacing between the coil plane and the EuT-surface. The highest field strength levels can be achieved using the shortest ring. There are further rings available on request in order to provide a certain scaling between coil current and magnetic field strength (e.g. 1 Amp coil current = 100 Amp/m field strength)


Application as magnetic field probe:

The FESP 5133 can also be used to measure existing magnetic fields. The open circuit output voltage is directly proportional to the magnetic field strength (at fixed frequency) or directly proportional to frequency (at constant magnetic field strength).


Number of turns: 36
Wire diameter: 1.26 mm Cu
Maximum coil current: 10 A (5 min.)
Nominal coil current: 5 A continuous
Max. magn. field strength: 1385 A/m (5 min.)
Nominal magn. field strength: 700 A/m continuous
Magnetic field strength, 1 A coilcurrent: (with 50 mm distance ring):

138.5 A/m

Current required for 1 A/m:
(with 50 mm distance ring)

7.22 mA
Magnetic field strength, 1 A coil current: (with 100 mm distance ring) 46.88 A/m

Current required for 1 A/m:
(with 100 mm distance ring)

21.3 mA
Flux density with 50 mA at 50 mm distance:

138.8 dBpT
136.8 dBµA/m

Inner coil diameter:

133 mm
Medium coil diameter: 135.5 mm
Spacing coil center to measurement plane: 50 mm / 100 mm
Mechanical dimensions:  0.16 m x 0.25 (0.3) m
Coil terminals: 4 mm Laborstecker (Standard) oder BNC
Shield: Electrostatic
Usable frequency range: 0 - 200 kHz
Inductance: ≈ 300 μH
Resonance frequency: >500 kHz


0.6 Ω


1.1 kg


MIL 461
EN 55103 - 2 A.2.1 b)
EN 55103 - 2 A.4.1


Datasheet FESP 5133