JPH06242154A - Voltage detector - Google Patents

Abstract

PURPOSE:To measure an electric characteristic of an object to be measured easily in a voltage detector. CONSTITUTION:Alternating current voltage, which is one of the electric characteristics of an object to be measured, is measured by bringing a detector probe 23 close to or into contact with the object to be measured. Tester probes 22, 24 are brought into contact with the object to be measured so as to measure the electric characteristic of the object to be measured. When the tester probe 22 is used, a switch cover 29 rotates with the tester probe 22 to be stored into the inside of a main body 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a function of measuring and displaying AC and DC voltages, currents and resistances in a contact state and a function of measuring and displaying AC voltage in a non-contact state or a contact state. Related to the voltage detector.

[0002]

2. Description of the Related Art Conventionally, a circuit meter (tester) has been widely used as a means for measuring and displaying electric characteristics such as AC and DC voltages, currents and resistances.

FIG. 8 is a schematic perspective view showing an example of a digital multimeter (DMM) which is one of the testers. The main body 10 is provided with a dial 11 for switching the mode of electric characteristics to be measured. The electrical characteristics of the measurement target are measured by the two tester probes 12 and 13 inserted in the main body 10, and the values are displayed on the liquid crystal display plate 14 arranged in the main body 10.

In such a structure, when it is desired to measure and display the voltage of a household outlet, for example, the operator turns the dial 11 to set the AC voltage and holds the two tester probes 12 and 13. Plug their tips into an outlet. As a result, the voltage of the outlet is measured and the value is displayed on the liquid crystal display board 14. The above tester is excellent in that it can easily measure various electrical characteristics such as the voltage, current, and resistance of the measurement target, but at the time of measurement, the operator holds the tester probe and attaches it to the measurement target terminal, etc. There is a risk of electric shock because they must be in contact,
There was a problem in terms of work safety. Further, recently, a closed type distribution board for low voltage is becoming more and more closed type in order to improve safety, so that it has been difficult to bring the tester probe into contact with a terminal of the distribution board or the like.

Therefore, a voltage detector has been developed which can measure and display the AC voltage of the measurement target by bringing the probe close to the measurement target. FIG. 9 is a schematic perspective view showing an example of a voltage detector. A detection probe 2 made of a conductive rubber or the like is attached to one end of the main body 1, and the detection probe 42 detects an AC voltage to be measured. The detected AC voltage is connected to the detection probe 2 and divided by the voltage dividing means built in the main body 1. Then, the output voltage of the voltage dividing means is measured by the measuring and displaying means which is connected to the voltage dividing means and built in the main body 1, and the value is displayed on the liquid crystal display plate 3 provided on the side surface of the main body 1. .

In such a structure, for example, when it is desired to measure and display the AC voltage of the insulation-coated wire, the operator holds the main body 1 of the voltage detector and presses the detection probe 2 against the surface of the insulation-coated wire, The switch 4 arranged on the main body 1 is pushed. As a result, the AC voltage of the insulation-coated wire is measured and the value is displayed on the liquid crystal display board 3. As described above, according to the voltage detector, the AC voltage can be measured and displayed on the measurement target in a non-contact manner, so that the safety of the voltage detection work can be improved.

[0007]

SUMMARY OF THE INVENTION In the above-mentioned voltage detector,
Since only the AC voltage to be measured can be measured, a tester had to be prepared when it was desired to measure the DC voltage or AC and DC currents and resistances to be measured. Therefore, there are disadvantages that the measurement work is troublesome and the cost for aligning the equipment is high. The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an inexpensive power detection device that can easily measure the electrical characteristics of a measurement target.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a device for measuring and displaying the electrical characteristics of a measurement target by bringing the measurement target close to or in contact with the measurement target. A first probe for measuring an AC voltage that is one of the electrical characteristics of the measurement target by bringing the measurement target close to or in contact with the measurement target; and for measuring the electrical characteristics of the measurement target by contacting the measurement target This is achieved by providing a second probe and switching means for switching to use of only one of the probes.

[0009]

According to the present invention, since the electric detection probe and the tester probe are both provided and the means for switching them is used according to the use, it is possible to easily measure the electric characteristics of the object to be measured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic perspective view showing an example of the electric power detection device of the present invention. At one end of the main body 21, a tester probe 22 for measuring AC and DC voltages, currents, resistances, etc. to be measured, and a voltage detection probe 23 for measuring AC voltage to be measured are provided. . The other end of the main body 21 is provided with a tester probe 24 as a ground terminal used together with the tester probe 22 when measuring AC and DC voltages, currents, resistances, and the like to be measured. On the upper surface of the main body 21, a power source on / off switch 25 and an electric characteristic mode changeover switch 26 are arranged. Further, on the side surface of the main body 21, a liquid crystal display panel 27 for displaying the measured electric characteristic value and an LED 28 for displaying an approximate range of the measured voltage are arranged.

Further, since the tester probe 22 and the detection probe 23 are provided at the same end, there is a risk of misuse or contact when measuring either one. A switching cover 29 which covers the electric probe 23 and serves to store the tester probe 22 in the main body 21 when the electric detection probe 23 is used.
Is provided. The switching cover 29 is provided so that it can rotate in the direction of the arrow shown in the drawing together with the tester probe 22.
It is pivoted to 1. That is, when the tester probe 22 is used, as shown in FIGS. 2A and 2C, the tester probe 22 is arranged so as to project from the main body 21, and the detection probe 23 is covered by the switching cover 29. Be seen. Then, when the detection probe 23 is used, the tester probe 22 is rotated together with the switching cover 29 and housed in the main body 21 as shown in (c) and (d) of FIG. Appears.

FIG. 3 is an exploded perspective view showing another example of the switching cover of the power detection device of the present invention. This switch cover
The detection probe cover 50 serves to cover the detection probe 23, and the tester probe arm 51 with the tester probe 22 is attached to the main body 21 so as to be coaxially rotatable. The tester probe arm 51 is provided with a stopper 52 as shown in FIG. 4, so that the detection probe cover 50 can rotate depending on the rotation of the tester probe arm 51 in one direction, and the detection probe cover 50 can be rotated. The tester probe arm 51 is rotatable depending on the rotation in the direction opposite to the tip direction. FIG. 5 is a schematic perspective view of the power detection device of the present invention with the power detection probe cover 50 and the tester probe arm 51 attached. The figure (a) is a state when no measurement is performed, the detection probe 23 is covered with the detection probe cover 50, and the tester probe 22 is connected to the tester probe arm 51.
Together with this, they are housed in the main body 21 and each probe 22, 23 is protected. FIG. 2B shows a state in which the detection probe 23 is used. The detection probe cover 50, the tester probe 22, and the tester probe arm 51 are the main body 2
It is stored in 1. FIG. 6C shows a state when the tester probe 22 is used, and the tester probe arm 51
Is arranged so as to project from the main body 21, and
3 is covered with a voltage detection probe cover 50. Then, in the case of the states of (b) to (c) of the same figure, by rotating the tester probe arm 51, the detection probe cover 50 is simultaneously rotated by the stopper 52.
It is possible to prevent the types of probes 22 and 23 from being exposed. Similarly, also in the case of the state of (c) from (b) in the same figure, by rotating the detection probe cover 50,
Since the stopper 52 also rotates the tester probe arm 51 at the same time, it is possible to prevent the two types of probes 22 and 23 from being exposed at the same time. As described above, when the tester probe 22 and the tester probe arm 51 are housed in the main body 21, the voltage detection probe cover 5
Since the rotation of 0 is free, only the detection probe 23 can be used. In addition, when the detection probe 23 is covered with the detection probe cover 50, the tester probe 2
Since 2 and the tester probe arm 51 can freely rotate, only the tester probe 22 can be used. Note that the voltage detection probe 23 may be rotatable with the switching cover, and the tester probe 22 may be covered by the switching cover.

FIG. 6 is a block diagram showing a detailed example of the circuit of the power detection device of the present invention. When using the power detection probe 23 of the power detection device, the switching cover 29 is rotated and housed in the main body 21 as described above. However, at the same time as this rotation operation, the power detection probe 23 and the tester probe 22 are switched. The probe changeover switch 42 is changed over to the voltage detection probe 23 side, the on / off switch 43 of the tester probe 24 is changed over to the off side, and the DMM 40 is set to the AC voltage measurement mode. The AC voltage of the measurement target 5 detected by the detection probe 22 is the coupling capacitance formed between the measurement target 5 and the detection probe 22, the series combination capacitor of the input capacitors 31 and 33, and the voltage dividing capacitor 32. The voltage is divided by and is input to the amplifier configured by the operational amplifier 36, the feedback resistor 37, and the voltage dividing resistor 38 via the impedance conversion circuit configured by the FET 34 and the source resistor 35. The signal amplified by the amplifier to an appropriate voltage is passed through the coupling capacitor 39 to the DMM 40.
Sent to.

Here, the input capacitor is composed of two capacitors 31 and 33 connected in series, but this is to prevent electric shock when one capacitor is destroyed. Further, the bias resistor 41 is for applying a DC bias to the gate terminal of the FET 34 of the impedance conversion circuit, and is set to a value sufficiently larger than the impedance of the voltage dividing capacitor 32 at the frequency of the measurement target 5. The voltage division ratio and frequency characteristics are not damaged. For example, a ceramic capacitor is used as the input capacitor 31, and a ceramic capacitor or a metallized film capacitor is used as the input capacitor 33.

On the other hand, when the tester probe 22 is used, the changeover cover 29 is rotated to cover the detection probe 23, but at the same time as this rotation operation, the probe changeover switch 42 is used.
Is switched to the tester probe 22 side, the on / off switch 43 of the tester probe 24 is switched to the on side, and the measurement mode of the DMM 40 is set to be interlockable with the on switch 26. The switching operation of the switches 42 and 43 by the rotation of the switching cover 29 may be mechanical or electrical. Figure 7
FIG. 4 is a configuration diagram showing another detailed example of the circuit of the power detection device of the present invention in correspondence with FIG. 3, and the same components are given the same reference numerals and the description thereof will be omitted. In this circuit, an input resistor 44 and a voltage dividing resistor 45 are inserted instead of the input capacitors 31 and 33 and the voltage dividing capacitor 32 of the circuit shown in FIG. In order to remove the voltage error due to the DC component, DC blocking capacitors may be inserted at the positions 46 and 47 in FIG.

[0016]

As described above, according to the power detection device of the present invention, in order to easily measure the electrical characteristics of the object to be measured, one device is provided with a power detection probe and a tester probe, and Since it is equipped with a switching means so that only one of them can be used mechanically or electrically,
The safety of measurement work can be improved. Further, since it is provided as an inexpensive device, one device has both the functions of a conventional tester and a voltage detector, so that portability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a power detection device of the present invention.

FIG. 2 is a plan view showing an example of a main part of the device of the present invention.

FIG. 3 is an exploded perspective view showing another example of the main part of the device of the present invention.

FIG. 4 is three views of the main part shown in FIG.

5 is a schematic perspective view of the main part shown in FIG. 3 mounted on the device of the present invention.

FIG. 6 is a configuration diagram showing a circuit example of the device of the present invention.

FIG. 7 is a configuration diagram showing another circuit example of the device of the present invention.

FIG. 8 is a schematic perspective view showing an example of a tester.

FIG. 9 is a schematic perspective view showing an example of a voltage detector.

[Explanation of symbols]

 1,10,21 Main body 2,23 Detection probe 3,14,27 Liquid crystal display board 4 Switch 11 Dial 12, 13, 22, 24 Tester probe 25,43 On / off switch 26 Mode selection switch 28 LED 29 Switching cover 31 , 33 input capacitor 32 voltage dividing capacitor 34 FET 35 source resistor 36 operational amplifier 37 feedback resistor 38 voltage dividing resistor 39 coupling capacitor 40 DMM 41 bias resistor 42 probe changeover switch 44 input resistor 45 voltage dividing resistor 46, 47 DC blocking capacitor 50 Detection probe cover 51 Tester probe arm 52 Stopper

Claims (4)

[Claims] 1. An apparatus for measuring and displaying an electrical characteristic of the measurement target by bringing the measurement target close to or in contact with the measurement target, which is one of the electrical characteristics of the measurement target by bringing the measurement target into proximity or contact with the measurement target. A first probe for measuring an AC voltage, and a second probe for measuring an electrical characteristic of the measurement target by bringing the probe into contact with the measurement target.
And a switching means for switching to use of only one of the probes. 2. The switching means is rotatable together with any one of the probes, covers the other probe when using the one probe, and uses the other probe. The electric detection device according to claim 1, wherein the probe is housed in the main body together with the one probe. 3. The switching means may cover a first switching means that is rotatable integrally with any one of the probes and a probe that is rotatable coaxially with the rotation and is the other probe. Possible second switching means, the second switching means covers the other probe when the one probe is used, and the first switching means when the other probe is used. The first switching means is housed in the apparatus body together with the one probe, and the second switching means is housed in the apparatus body together with the one probe when neither of the probes is used. The voltage detector according to claim 1, wherein the other probe is covered. 4. The power detection device according to claim 1, wherein the switching means turns on / off the electrical connection of each probe simultaneously with the rotation.