JPS6123813Y2 - - Google Patents

Description

[Detailed description of the invention] This utility model detects the impedance of the circuit under test using the same magnetic core in order to detect the impedance of the circuit under test without electrical contact.
It is characterized in that the impedance of the circuit under test is detected by detecting this oscillating force, which is regarded as the oscillating force of a feedback oscillating circuit formed through the same magnetic core, and an embodiment thereof will be explained with reference to drawings. Then, it is as follows.

The configuration of the present invention is as shown in FIG. The line 3 and the amplifier 5 constitute a feedback oscillator, and the feedback oscillator's oscillation force detector 6 is further connected to the feedback oscillator.
The oscillation force of the feedback oscillator is controlled by the value of the circuit impedance 7 of the control winding 4, and the circuit impedance of the control winding 4 is electrically controlled by the oscillation force detector 6. It is characterized by non-contact detection. The circuit impedance Z7 of the control winding 4 in FIG.
FIG. 2 shows the relationship between the magnitude of A and the oscillation force A of the feedback oscillator mentioned above. In this figure, a indicates the cutoff region of the oscillation force, b indicates its transition region, and c indicates its saturation region.

First, an example will be described with reference to transition region b in FIG. Conventionally, methods for measuring impedance include the resonance method and the impedance bridge method, but these tend to require complicated circuit configurations and troublesome calculations.

However, according to the present invention shown in FIG. 1, the conventional troubles are alleviated and it becomes possible to easily detect the magnitude of impedance. In the transition region b of FIG. 2, Z≒kA holds true, where k is a proportionality constant. Therefore, by detecting the oscillation force in FIG. 1, the circuit impedance 7 of the control winding 4 can be linearly connected. In particular, if the impedance to be measured of the external circuit connected to the control winding 4 is sufficiently large compared to the impedance of the control winding 4, the measured value can be directly regarded as the impedance to be measured of the external circuit. FIG. 3 shows an example of this implementation circuit. In this figure, 8 is a power supply, 9 is an oscillation frequency control capacitor, 11 is an amplification transistor, 12 is a DC blocking capacitor, and 13 and 14 are bias resistors. Here, a case is shown in which an AC voltmeter (or ammeter) is used as the oscillation force detector 6, that is, the impedance detector. Of course, a rectifier detector, a DC voltmeter (or ammeter), or the like may be used as the oscillation force detector described above. In this way, according to this invention, the conventional troubles are alleviated, and it becomes possible to detect the magnitude of impedance without electrical contact.

Next, an example will be described with reference to the cut-off region a to the saturation region c in FIG. In this case, the oscillation force changes from the above-mentioned cutoff region a through the transition region b to the saturation region c due to a change in the circuit impedance 7 of the control winding 4 shown in FIG. Here, if the cutoff region a is a logic "0" (or "1") and the saturation region c is a logic "1" (or "0"), the circuit changes through the change in the circuit impedance 7 of the control winding 4 described above. The impedance state can be turned on and off electrically without contact.
Off detection, that is, digital detection becomes possible. By the way, since the circuit voltage V, current I and impedance Z have the relationship Z=V/I, the voltage V and current I of the circuit under test
If you know, you can know the state of the impedance Z of the circuit.

Conventionally, as a means for detecting this current, there is a method of detecting a magnetic field generated by the current in a part of a circuit using a Hall element or a magnetoresistive element. However, these sensing elements can be used alone when the circuit current is particularly large, that is, under strong magnetic fields;
Under the weak to medium magnetic field that is normally used, a gap is provided in a part of the magnetic core with high magnetic permeability, and the above-mentioned sensing element is inserted into the gap to compensate for the sensitivity. Therefore, it has disadvantages such as the need to process hard magnetic materials and its mechanical strength is inferior to that of a magnetic core without voids.

However, according to the present invention shown in Fig. 1, a magnetic core is used in the same way as the method of detecting impedance by current detection described above, but not only does the Hall element and magnetoresistive element become unnecessary, but the magnetic permeability is also reduced. Large magnetic materials can be used as is without any processing such as creating gaps. Therefore, it is magnetically stable, mechanical strength is maintained, and magnetic resistance can be lowered, so there is almost no influence from the above-mentioned variations in the spatial shape of the windings of the magnetic core 1, and high and low impedance states are achieved without electrical contact. can be measured.

Moreover, even if the circuit under test of the control winding 4 described above is in an on-off operation including a DC power supply, the oscillation force in FIG. The impedance detection device of the invention has only an effect on the DC resistance value of the control winding 4 (which may just pass through the magnetic core) mentioned above on the circuit under test. Conversely, when the circuit under test is off,
That is, in the open circuit state, the aforementioned oscillating force is in the aforementioned saturation region c, but since the control winding circuit is open, the aforementioned oscillating force does not affect the aforementioned control winding circuit. Therefore, whether the circuit under test is in an on or off state, the impedance detection circuit of the present invention has almost no influence on the circuit under test.

On the other hand, even if the above-mentioned circuit under test is an on-off operation circuit including an AC power supply, the above-mentioned control winding 4
If the impedance is small enough to cause no problem, the effect on the circuit under test can be ignored, as in the case of the DC power supply described above.

FIG. 4 is a concrete example of a circuit from the cut-off region a to the saturation region c of FIG. 2, and shows the case where it is applied as a lamp life measuring device. Fourth
In the figure, 10 is a power supply, 15 is a DC blocking capacitor, 16, 17, 18 is a detection rectifier circuit, 19
is an amplification transistor, and 20 is an output relay. When load life, such as lamp life, is significantly affected by a small change in applied voltage by a factor of 10 ¹² to 10 ¹³ , it is necessary to insert a capacitor electrically between the power supply and the circuit under test to affect the circuit under test. It is preferable that there is no giving at all. Conventionally, meters
The circuit status has been detected by inserting a relay or low resistance into a part of the circuit, or by bringing a temperature-sensitive element or a photo-sensitive element close to each other, but each has an effect on the circuit under test.
It was expensive and had problems such as response speed and ambient optical noise. However, according to the present invention, all of the above-mentioned problems can be solved, and advantages such as low cost, high speed response, wide effective temperature range, and no influence of optical noise can be utilized with almost no effect on the circuit under test. .

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of the magnetic feedback oscillation type non-contact impedance detection device of the present invention, Fig. 2 is a relationship diagram between the circuit impedance Z of the control winding and the oscillation force A of the feedback oscillation circuit, and Fig. 3 is An example of a linear implementation circuit using transition region b in Fig. 2;
An example of a digital implementation circuit using the cutoff region a to the saturation region c in the figure.

Claims (1)

[Scope of utility model registration request] An input winding, an output winding, and a control winding are wound around the same magnetic core, a feedback oscillator is configured by the input winding, the output winding, and the amplifier, and the oscillation of the feedback oscillator is A force detector is provided to control the oscillation force of the feedback oscillator according to the value of the circuit impedance of the control winding, and the circuit impedance of the control winding is electrically controlled by the oscillation force detector. A magnetic feedback oscillation type non-contact impedance detection device that is characterized by non-contact detection.