JPH0727867A - Magnetic sensor - Google Patents

Abstract

PURPOSE:To obtain a magnetic sensor which is not affected by light, etc., can be installed in a small space, and is not always required to be in contact for actuation. CONSTITUTION:A magnetic sensor is provided with a power source 2 which supplies a bias current to a coil 1 for generating magnetic fields and a resistor 3 which controls the power source 2 and a magnetic field is generated by making the bias current to flow to the coil 1. When a material having large specific permeability crosses the magnetic field, the inductance of the coil 1 varies. The variation is detected by means of an external circuit.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The sensor of the present invention uses other conventional sensors, such as a crime prevention device, a swing analysis device, and a speed measuring device, on the assumption that it operates on a substance having a large relative magnetic permeability. It can be used in any field.

[0002]

2. Description of the Related Art In the past, what has been used as a sensor has been used as a sensor the change in energy generated by contact with light, voice, light rays such as infrared rays.

[0003]

SUMMARY OF THE INVENTION A conventional sensor has a fundamental element of operating by contact, that is, it operates by generating a sound at the time of contact or by contact with a light ray such as infrared rays. It required a large space to install. In addition, it tends to be affected by light from a fluorescent lamp or the like, which tends to cause a malfunction. Therefore, it is an object to operate without being in contact with each other, install in a small space, and not be affected by light.

[0004]

According to the present invention, a bias current is passed through a coil and the change in energy generated in the coil is detected by an external circuit to recognize the passage of a substance, which is used as a sensor. It is an attempt to solve a problem.

[0005]

[Operation] A bias current is applied to the coil to generate a magnetic field,
A substance having a large relative magnetic permeability is passed over this coil. As a result, the inductance of the coil changes, and the passage of the substance can be recognized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to the accompanying drawings.
Reference numeral 1 is a coil for generating a magnetic field, 2 is a power source for supplying a bias current, and 3 is a resistor for controlling the current. A bias current is passed through this coil, and the golf club of 4 is shaken so as to pass over the coil.

When the golf club crosses the magnetic field generated in the coil, the inductance of the coil changes. When this change is viewed on the synchroscope 6 it can be seen that the waveform of the inductance, which was kept constant, changed as shown in FIG. 2 and the energy stored in the coil changed.
By confirming this change in energy with an external circuit, it can be recognized that the substance has passed. Further, the speed can be measured with the width of the time axis of A and B.

[0008]

As described above, the sensor of the present invention is not affected by light or the like, and can be installed in a smaller space than before, and can be operated without contact. Further, in contrast to the contact which is a basic element of the conventional sensor, the sensor of the present invention operates by the element of crossing over the magnetic field, and thus becomes a sensor different from the conventional one.

[Brief description of drawings]

FIG. 1 is a system diagram of a sensor of the present invention.

FIG. 2 is a change in inductance seen on a synchroscope.

[Explanation of symbols]

 1 coil 2 power supply 3 resistance 4 golf club 5 sensor detection unit 6 synchroscope

Claims (1)

[Claims] 1. The present invention provides a sensor for a change in energy generated by passing a bias current through a coil.