# US 5,705,861 A · Magnetic field pulse generator

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- Number: US 5,705,861 A
- Document ID: US5705861A
- Status: Granted
- Kind: A
- Application number: 08/573,729
- Filed: 1995-12-18
- Granted: 1998-01-06
- Earliest claimed: 1995-12-18
- Assignees: Siemens Matsushita Components GmbH & Co. KG
- Inventors: Mauricio Esguerra
- Web page: https://patentgrep.com/patent/US5705861A

## CPC

- G01V 3/101: {by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil (measuring impedance or characteristics derived therefrom G01R27/00, e.g. quality factor G01R27/26)}
- H01F 7/20: without armatures (cores H01F3/00; coils H01F5/00 {; shaping metal by applying magnetic forces B21D26/14; electromagnets specially adapted for NMR applications G01R33/381})
- H03K 17/94: characterised by the way in which the control signals are generated
- H03K 17/9515: {using non-linear magnetic devices}
- H03K 17/9517: {using galvanomagnetic devices}
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A magnetic field pulse generators has an electrical coil and a magnetizable element being inductively coupled thereto, for together radiating a magnetic field into an external space. In order to switch off the magnetic field in the external space, the magnetizable element can be driven to saturation by a pulsed current in the coil at which the material of the coil core has not yet reached saturation.

## Claims

### Claim 1

A magnetic field pulse generator, comprising:
an electrical coil having a core formed of a material;
a magnetizable element inductively coupled to said electrical coil, said magnetizable element formed of a ferromagnetic material reaching saturation at a magnetic induction small in relation to an induction necessary to saturate said material of said core;
said magnetizable element and said electrical coil together radiating a magnetic field into an external space, the magnetic field in the external space being switched on and off by electrically switching over said magnetizable element from an unsaturated to a saturated state; and
pulse voltage source coupled to said coil for super-imposing a pulsed current on a current generating the magnetic field, the pulsed current being sufficient to generate a magnetic induction at which said magnetizable element reaches saturation.

### Claim 2 (depends on 1)

The magnetic field pulse generator according to claim 1, wherein said coil has an open side, said core of said coil is a half-shell-type core, and said magnetizable element is placed onto said open side of and closes off said coil.

### Claim 3 (depends on 2)

The magnetic field pulse generator according to claim 2, wherein said coil has a center, said magnetizable element has a side facing said open side of said coil, said side of said magnetizable element has a conical shape with a vertex lying in said center of said coil, and said open side of said coil is matched to said conical shape of said magnetizable element.

### Claim 4 (depends on 1)

The magnetic field pulse generator according to claim 1, including an electrically conductive, metallic carrier housing into which said electrical coil and said magnetizable element fit flush.

### Claim 5

A magnetic field pulse generator for an inductive proximity switch, comprising:
an electrical coil having a core formed of a material;
a magnetizable element inductively coupled to said electrical coil, said magnetizable element formed of a ferromagnetic material reaching saturation at a magnetic induction small in relation to an induction necessary to saturate said material of said core;
said magnetizable element and said electrical coil together radiating a magnetic field into an external space, the magnetic field in the external space being switched on and off by electrically switching over said magnetizable element from an unsaturated to a saturated state; and
a pulse voltage source coupled to said coil for super-imposing a pulsed current on a current generating the magnetic field, the pulsed current being sufficient to generate a magnetic induction at which said magnetizable element reaches saturation.