TWI647458B - Capacitor insulation resistance measuring device - Google Patents

Abstract

An insulation resistance measuring device that can perform high-accuracy and high-speed measurement of the insulation resistance of a capacitor is provided.

An insulation resistance measuring apparatus includes: a measurement terminal that is disposed in contact with an electrode of one of capacitors to be measured, and is connected to a measurement terminal of a constant voltage constant current supply circuit to be in contact with an electrode connected to the other side of the capacitor a measurement terminal and a transmission resistor Ri connected to the measurement terminal, and a current-voltage conversion circuit including an operational amplifier and a resistor connected between the inverting input terminal and the output terminal of the operational amplifier, and then connected to the An insulation resistance measuring device for a capacitor of a voltage measuring device on the output side of a current-voltage conversion circuit, characterized in that: the output side wiring portion of the operational amplifier of the current-voltage conversion circuit is connected in series and arranged in opposite directions to one another a body, the Zener diode is further connected to a resistor connected to the ground, and a wiring portion between the Zener diode and the resistor connected to the ground and the input side wiring portion of the operational amplifier are connected in parallel One pair of mutually oppositely arranged is connected to the diode, and further, connected to the resistor Ri in parallel Polar body.

Description

Capacitor insulation resistance measuring device

The present invention relates to an insulation resistance measuring device for a capacitor, In particular, it relates to an insulation resistance measuring device that is effective for measuring an insulation resistance of a large number of minute capacitors (wafer capacitors) at high speed. In particular, the present invention relates to an on-insulation measuring device that is incorporated in an automated wafer capacitor inspection device, and can be effectively used for measuring an insulation resistance of a large number of wafer capacitors with high precision and high speed.

With mobile phones, smart phones, LCD TVs, video games The production of small electrical products such as theaters has increased, and the production of micro-chip electronic components incorporated in such electrical products has increased significantly. As a typical chip electronic component, there is a chip capacitor (also referred to as a chip capacitor) which is formed of an insulating material and a body portion which is provided on both end faces of the body portion. form.

In recent years, smaller electrical products have been incorporated into wafer electronic components. Forming, then, in response to an increase in the number of electronic components of the wafer incorporated in the electrical product, the electronic components of the wafer are gradually becoming extremely small. For example, regarding wafer capacitors, in recent years, extremely small sizes have been used (for example, referred to as 0402 wafers, A wafer capacitor of 0.2 mm × 0.2 mm × 0.4 mm in size). Such tiny wafer capacitors are produced in large quantities in tens of thousands to hundreds of thousands of units.

Regarding the electronic components of the wafers that are incorporated in electrical products, In order to reduce the defective product rate of an electrical product caused by defects in the electronic component of the wafer, generally, the required performance of the mass-produced electronic component of the wafer is inspected in advance. Specifically, regarding the wafer capacitor, the electrical characteristics of the insulation resistance and the static capacitance are inspected in advance for the total number.

The electrical properties of a large number of wafer electronic components such as wafer capacitors In order to perform the high-speed inspection automatically, in recent years, a transfer disk (a wafer electronic component temporary holding plate) having a plurality of through holes is generally used for performing chip electronic parts. Inspection and selection of electrical characteristics (ie, wafer electronic part inspection sorting device). In the transporting disk, a plurality of through holes for temporarily storing the electronic components of the wafer to be inspected are formed in parallel in a plurality of rows of three or more rows along the circumference. Then, when the wafer electronic component inspection and sorting device is used, the through-hole of the transporting disk in the intermittently rotating state temporarily stores and holds the electronic component of the wafer, and the electronic component of the wafer is held by the through hole of the transporting disk. Each of the electrodes is in contact with a pair of electrode terminals (inspection contacts) attached to the rotation path of the transfer disk, and the predetermined electrical characteristics of the electronic component of the wafer are measured. Next, based on the measurement result, the wafer electronic is implemented. The part is discharged from the through hole of the transporting disc to be sorted and sorted (or sorted) in a predetermined container.

That is, the most recent inspection of wafer electronic parts The sorting device can be said to be a wafer electronic component transfer disc including a base and a rotatable shaft supported on the base (however, the wafer electronic component transporting disc can temporarily accommodate the wafer having the electrodes on the opposite end faces) The row of the through holes of the electronic component is formed in three or more rows along the circumference, and then sequentially disposed along the rotation path of the transporting disk, and the through hole of the transporting disk is supplied to the electronic component of the chip for accommodating the electronic component of the chip. The accommodating portion (supply accommodating region), the electronic component electrical property inspection unit (inspection region) for inspecting the electrical characteristics of the electronic component of the wafer, and then classifying the checked electronic component of the wafer according to the inspection result Chip electronic component inspection and sorting device for the chip electronic component classification section (classification area).

As an example of a wafer electronic component inspection and sorting device, The device described in Patent Document 1 is cited. In the patent document 1, the wafer electronic component inspection and selection device using the above-described structure is described, and the electronic components of the wafer to be inspected are accommodated and held in the through-holes of the transporting disk in a state in which they are placed close to each other, and then, The electronic components of the chip are electrically connected to the inspector through the contacts, and then the inspection voltage is applied to the electronic components of the wafers from the inspector, and the inspectors detect the application of the voltages for the inspections on the respective chips. A method of improving the electrical continuity of the electronic components of the wafer by the continuity of the electrical current generated by the component.

On the other hand, as an insulation resistance measuring device for a capacitor As an example, the measuring device described in Patent Document 2 is known. In other words, Patent Document 2 discloses that a measurement terminal including a power supply and a current limiting circuit connected to the power supply and an electrode connected to one of the capacitors (DUTs) to be connected to the current limiting circuit is used. For the determination a measurement terminal disposed to contact the other electrode of the capacitor (DUT) of the terminal, a resistor Ri connected to the measurement terminal, and a resistor Ri connected to the resistor Ri, and including an operational amplifier and an inverting input terminal connected to the operational amplifier A current-voltage conversion circuit that outputs a resistance between the terminals, and then an insulation resistance measuring device connected to the voltage measuring device on the output side of the current-voltage conversion circuit to measure a leakage current, thereby measuring the insulation of the capacitor (DUT) Device for resistance.

Insulation resistance measurement of the capacitor described in Patent Document 2 The basic structure of the fixed device (i.e., the device for measuring the insulation resistance of the capacitor by measuring the leakage current of the capacitor) is disclosed in Fig. 1 together with the leakage current measuring circuit incorporated in the device.

In Figure 1, the insulation resistance measuring apparatus capacitor line comprises current includes a power source (ground V ₁₎ connected to the power limiting circuit (resistor R & lt _1), and with a capacitor connected to the current limiting measurement target circuits of a measurement terminal (T ₁ ) that is in contact with one of the electrodes (D1) and a measurement terminal (T ₂ ) that is placed in contact with the other electrode of the capacitor (DUT) connected to the measurement terminal, and is connected to the measurement terminal a resistor Ri connected to the resistor Ri and including a current-voltage conversion circuit (IV amp) of the operational amplifier 11 and a resistor 12 connected between the inverting input terminal and the output terminal of the operational amplifier, and then connected to the current A device for measuring the voltage on the output side of the voltage conversion circuit (V).

That is, the insulation resistance of the capacitor is used, for example, to include The device of the circuit shown in FIG. 1 is added. First, the capacitor (DUT) is charged, and then the charging is completed by the charging of the detecting capacitor. It is measured by the current (the leakage current of the capacitor). Furthermore, in order to measure the leakage current of the capacitor, it is necessary to convert the current value of the leakage current into a voltage value. Therefore, a current-voltage conversion circuit including a current-converting circuit for converting the current value into a voltage value is generally used, which is generally referred to as IV. The circuit of the amplifier.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] WO2014/010623A1

[Patent Document 2] Japanese Patent Laid-Open No. Hei 8-262076

As shown in FIG. 1, the IV amplifier is an amplifying device including a current-voltage conversion circuit of an operational amplifier and a resistor connected between the inverting input terminal and the output terminal of the operational amplifier. Furthermore, an IV amplifier can also be understood as a current-voltage conversion circuit that also includes a resistor Ri disposed on its input side.

According to the review by the inventors of the present invention, when the insulation resistance of the capacitor is measured using the insulation resistance measuring device of the general structure shown in FIG. 1, the IV amplifier is saturated, and it is found that the time required for the measurement of the IV amplifier is saturated. lengthen. In other words, since a power supply device including a constant current circuit is used as a power supply device for charging a capacitor, charging of a constant current is performed until the capacitor is fully charged, but actually, when the capacitor is short-circuited, etc. Still large current inflow When the amplifier is turned to an IV amplifier, a virtual short circuit of the IV amplifier collapses, and charging of the above constant current cannot be performed. Because of the collapse of the virtual short circuit, the IV amplifier is saturated, and as a result, the time required until the capacitor is fully charged tends to become long. The time required to fully charge becomes a problem, especially when it is necessary to measure the insulation resistance of a large number of capacitors at high speed, that is, to insulate the insulation resistance of a large number of wafer capacitors by using the previously described wafer electronic component inspection and sorting device. In the measurement state or the like, the measurement efficiency (the number of wafer capacitors capable of measuring electrical characteristics per unit time) is lowered, so that it is a serious problem in the measurement of the electrical characteristics of the actual wafer capacitor. .

Therefore, the main subject (purpose) of the present invention provides high speed Further, an insulation resistance measuring device for measuring the insulation resistance of a capacitor, in particular, a wafer capacitor of a large number of small-sized capacitors, is measured with high precision.

In order to achieve the above object, the inventor of the present invention firstly checks the saturation of the IV amplifier which occurs when the insulation resistance of the capacitor is measured by using the insulation resistance measuring device having the structure shown in FIG. 1, and reviews the prevention of the IV amplifier before the full charge. Means of the occurrence of virtual short circuits. Then, as a result of the review, the current-voltage conversion circuit incorporated in the IV amplifier (that is, the current-voltage conversion circuit including the operational amplifier and the resistor connected between the inverting input terminal and the output terminal of the operational amplifier) is found. The output side wiring portion of the operational amplifier is connected in series and arranged in opposite directions to one another to align the diodes, and then, in the alignment The pole body is further connected with a resistor connected to the ground, and further, the wiring portion between the aligned nanodiode and the resistor connected to the ground and the input side wiring portion of the operational amplifier are connected in parallel and mutually opposite One of the diode connections is configured to avoid the occurrence of a virtual short circuit in the current-voltage circuit of the IV amplifier before the full charge.

The inventor of the case continued to review the results and found that the use can be borrowed A current-voltage circuit that avoids the occurrence of a virtual short circuit by arranging an aligned nano-diode under the foregoing conditions, and by arranging the connection diode in parallel with the resistance Ri on the input side of the current-voltage circuit, the IV amplifier can be suppressed. The occurrence of the saturation phenomenon before the full charge realizes the charging operation of the continuous constant current from the start of charging to the full charge, and the invention can be shortened by shortening the time required from the start of charging to the full charge.

Therefore, the present invention is firstly an insulation resistance measuring device. The method includes: a constant voltage constant current supply circuit; and a measurement terminal that is in contact with an electrode connected to one of the capacitors to be measured by the constant voltage constant current supply circuit; and the other of the capacitors connected to the measurement terminal a measurement terminal disposed to be in contact with the electrode, a resistor Ri connected to the measurement terminal, and a current voltage connected to the resistor Ri and including an operational amplifier and a resistor connected between the inverting input terminal and the output terminal of the operational amplifier And a switching circuit, and an insulation resistance measuring device of the capacitor connected to the voltage measuring device on the output side of the current-voltage conversion circuit, wherein the output side wiring portion of the operational amplifier of the current-voltage conversion circuit is connected in series Arranging one of the opposite poles in alignment with each other, and aligning the two diodes with the resistor connected to the ground, and The wiring portion between the one of the aligned nano-diodes and the resistor connected to the ground and the input-side wiring portion of the operational amplifier are connected to the diode by one of the parallel and mutually opposite poles, and further, the resistor Ri Connect the diodes in parallel.

Moreover, the present invention is a current-voltage conversion circuit, which is a package A current-voltage conversion circuit including an operational amplifier and a resistor connected between the inverting input terminal and the output terminal of the operational amplifier, wherein the output side wiring portion of the operational amplifier is connected in series and arranged in opposite directions Aligning the diodes, the aligning diodes are connected to the resistors connected to the ground, and the wiring portion between the aligning diodes and the resistor connected to the ground and the input side of the operational amplifier The wiring portion is connected to the diode by one of the parallel and mutually reversed configurations.

By using the insulation resistance measuring device of the capacitor of the present invention, the insulation resistance of the capacitor can be measured with high precision and in a shortened time. Therefore, the insulation resistance measuring device of the capacitor of the present invention can be used to inspect the sorting device for the electronic component of the wafer, which is used for inspecting the insulation resistance of a large number of wafer capacitors, so that the inspection accuracy can be lowered and the inspection speed can be improved. That is, the time required for the inspection work can be shortened.

V ₁ ‧‧‧ power supply

R ₁ ‧‧‧Resistance of current limiting circuit

Vc‧‧‧ constant voltage constant current power supply

Ro‧‧‧ equivalent output resistance

T ₁ , T ₂ ‧‧‧measuring terminal

DUT‧‧‧ Capsules for measuring objects

I‧‧‧current

Voltage across Vd‧‧‧DUT

Ri‧‧‧resistance

IV amp‧‧‧IV amplifier (current and voltage amplifier)

11‧‧‧Operational amplifier

12‧‧‧resistance

13‧‧‧Zina diode

14‧‧‧resistance

15‧‧‧Parallel diode

V‧‧‧ voltmeter

[Fig. 1] discloses the use of the insulation resistance measuring device of the prior capacitor An example of a leakage current measurement circuit for a capacitor.

Fig. 2 is a view showing an example of a leakage current measuring circuit of a capacitor used in an insulation resistance measuring device of a capacitor according to the present invention.

FIG. 3 is a graph showing information on changes in the charging voltage of the capacitor when the leakage current measurement of the capacitor (reference example) is performed using a leakage current measuring circuit in which the diode (D) is not arranged in parallel with the resistor Ri.

[Fig. 4] A leakage current measuring circuit (leakage current measuring circuit of an insulation resistance measuring device of a capacitor of the present invention) in which a resistor (R) is arranged in parallel with a resistor Ri, and a leakage current measurement of a capacitor is performed (the present invention A graph of the data of the change in the charging voltage of the capacitor of the embodiment.

Having described the following in accordance with the attached FIG. 2 The construction of the insulation resistance measuring device of the capacitor.

The insulation resistance device of the capacitor shown in FIG. 2 includes a device having a constant voltage constant current power supply (grounded Vc) and an equivalent output resistance (Ro) connected to the power supply, and connected to the equivalent output. a measurement terminal (T ₁ ) that is in contact with one of the capacitors (DUT) of the capacitor to be measured, and a measurement terminal (T ₂ ) that is placed in contact with the other electrode of the capacitor (DUT) connected to the measurement terminal. a resistor Ri of the measurement terminal, a diode (D) connected in parallel to the resistor Ri, and a resistor connected to the resistor Ri, and including an operational amplifier 11 and a resistor connected between the inverting input terminal and the output terminal of the operational amplifier 12, then, in the output side wiring portion of the operational amplifier 11, connected in series and oppositely arranged one of the aligned nano-diodes 13, in the aligned nano-diode 13, and further connected to the grounding resistor 14, and further And connecting the wiring portion between the one of the aligned nano-diodes 13 and the resistor 14 connected to the ground to the input-side wiring portion of the operational amplifier 11, and connecting the pair of diodes 15 in parallel and mutually oppositely arranged. of Voltage measurement with the output side of the current voltage conversion circuit (IV amp-1), and then, connected to the current-voltage conversion circuit (IV amp-1) of (V). Furthermore, the constant voltage constant current source and the equivalent output resistance connected to the power source form a constant voltage constant current supply circuit.

2, the insulating power of the capacitor according to the present invention is known. The resistance measuring device is different from the insulating resistance measuring device of the previous capacitor of FIG. 1 in that the output side wiring portion of the operational amplifier 11 mainly incorporated in the current-voltage conversion circuit incorporated in the IV amplifier is connected in series and arranged in opposite directions to each other. The alignment diode 13 is connected to the resistor 14 connected to the ground, and the wiring portion between the alignment nano diode 13 and the resistor 14 connected to the ground is connected to the operation. The input side wiring portion of the amplifier 11 is connected to the diode 15 by one of the parallel and mutually reversed arrangement portions, and then the resistors Ri are arranged in parallel to connect the diodes (D).

The capacitor of the present invention is used in an insulation resistance measuring device One of the novel current-voltage conversion circuits is inserted into the alignment diode 13 to prevent the output of the operational amplifier 11 from being saturated. That is, when the output voltage exceeds the breakdown voltage of the Zener diode 13, the Zener diode 13 operates (ie, turns ON), thereby preventing the virtual short circuit of the operational amplifier 11 from collapsing, thereby prevent The output voltage becomes higher. Furthermore, the reason why the aligned nano-diodes are arranged opposite each other is to correspond to both the situation in which the operational amplifier starts to saturate in the forward direction and the situation in which the operational amplifier starts to saturate in the negative direction.

On the other hand, an aligned nanodiode 13 is connected to the connection The wiring portion between the ground resistors 14 and the input side wiring portion of the operational amplifier 11 is connected to the diode (parallel diode) 15 in parallel and mutually oppositely arranged to have a Zener diode The leakage current bypass function of the polar body 13. That is, the newly inserted Zener diode has a small leakage current, so when a small current is measured, that is, when the feedback resistance is high, the leakage current from the Zener diode becomes a flow. The current of the feedback resistor cannot be ignored, and there is a cause of an error in the measured value of the leakage current of the capacitor to be measured. The circuit including the parallel diode 15 separates the Zener diode 13 from one end of the operational amplifier, and is connected to the grounded resistor from the parallel diode 15 to carry the Zener diode 13 from the Zener diode 13 The leakage current flows through the ground. Further, when the voltage of the leakage current of the Zener diode 13 and the "resistance connected to the ground from the parallel diode 15" exceeds the ON voltage of the parallel diode 15, that is, the Zener diode 13 At the time of collapse, the Zener diode 13 is connected to the operational amplifier and functions to maintain a virtual short circuit of the IV amplifier.

Next, the insulation resistance measurement of the capacitor of the present invention will be described. In the fixed device, the role of the diode (D) incorporated in a manner in which the resistors Ri are connected in parallel is used.

Operational amplifier of an insulation resistance measuring device incorporated in a capacitor 11, as long as it is an element showing ideal characteristics, in theory, it is not necessary to connect the resistor Ri to the operational amplifier. However, when the operational amplifier is not an amplifier showing the ideal characteristics, the operation of the operational amplifier itself is unstable in the state where the resistance Ri is not connected. As a result, oscillation occurs, and at this time, normal IV conversion (current voltage) cannot be performed. Conversion). Therefore, in the insulation resistance measuring circuit of the capacitor actually used, as described above, the resistor Ri is inserted between the capacitor (DUT) and the operational amplifier 11. As the resistor Ri, generally, a resistor of several hundred Ω to several kΩ is used. The resistance Ri is stable as the resistance value is larger. However, if the resistance value is large, the capacitance C of the capacitor forms a time constant (C×Ri). Therefore, the charging time is excessively consumed, and the measurement time is extended to become used. Shorten the measurement time barrier. In the insulation resistance measuring device of the capacitor of the present invention, since the resistor Ri is connected in parallel to connect the diode (D), the resistor Ri is bypassed by the diode, thereby stopping the capacitor from being charged during charging of the capacitor. The leakage current flows through the resistor Ri, and then, when the charging is completed (that is, when the leakage current flows through the IV amplifier), the resistor Ri operates, so that the oscillation of the IV amplifier can be suppressed.

For the reason described above, in the insulation resistance measuring device of the capacitor of the present invention, the measurement time can be shortened while avoiding the instability of the measurement circuit.

Furthermore, as a diode arranged in parallel with the resistor Ri (D), the diode (D) whose voltage across the resistor Ri is lower than the ON voltage is selected. However, since the normal diode indicates an ON voltage of 0.6 to 0.7 V, the normal value can be used without particular limitation. Dipole (for example, PN junction II Polar body).

Next, embodiments and reference examples of the present invention are disclosed.

[Examples] [Reference Example 1]

The insulation resistance measuring device of the capacitor shown in FIG. 2 with the drawing shown in FIG. 2, and the voltage at the time of charging of the charging operation of the capacitor due to the constant current predicted when the resistor Ri is not arranged in parallel with the diode (D) is as follows Shown.

Constant current end voltage (Ve)=Vc-I‧(Ri+Ro)

Vc: the voltage of the constant current supplied from the power supply

I: current flowing through the capacitor (DUT)

Ri: resistance value of input resistor Ri

Ro: resistance value of output resistor Ro

That is, the constant current charging is due to the influence of the input resistance Ri and the output resistance Ro, and it is predicted that the higher the charging voltage, the lower the charging current.

Next, when the change of the charging voltage when Vc=±50 V, Ro=35 Ω, Ri=100 Ω, and I=30 mA is calculated by the above-described calculation formula, the calculation will be described later.

Ve=50-0.03×(35+100)=45.95(V)

Therefore, until Ve is about 46 V, it is a constant current charge of 30 mA, but thereafter, it becomes a charging current in accordance with the calculation formula described later.

As can be seen from the above calculation formula, the closer to the full charge, the smaller the charging current, and the above-described predicted charging rate is lowered.

[Reference Example 2]

FIG. 3 discloses an insulation resistance measuring device of the capacitor shown in FIG. 2 with the drawing shown in FIG. 2, and when the resistor Ri is not arranged in parallel with the diode (D), the charging operation of the charging operation of the capacitor due to the constant current is measured. The graph of the voltage change".

The conditions for measuring this voltage change are as follows.

Charging voltage: 50V, charging current: 30mA, charging time: 1 second, input resistance: 1kΩ, measuring object capacitor (DUT): 10μF

From Fig. 3, when the diode (D) is not arranged in parallel with the resistor Ri, it can be confirmed that the constant current charging end voltage is low, and after the constant current charging is completed, smooth charging is performed.

[Example 1]

As shown in Fig. 2, the insulation resistance measuring device of the capacitor shown in Fig. 2 (the voltage at the charging of the capacitor due to the constant current) predicted in the diode (D) in which the resistor Ri is connected in parallel is as follows. Calculation.

Constant current end voltage (Ve)=Vc-(I×Ro+D)

Vc: the voltage of the constant current supplied from the power supply

I: current flowing through the capacitor (DUT)

Ro: resistance value of output resistor Ro

D: the voltage of the diode in the forward direction

Then, using the above calculation formula, calculate Vc=50V, When the change of the charging voltage when Ro = 35 Ω, I = 30 mA, and D: 1.5 V is calculated as follows.

Ve=50-(0.03×35+1.5)=47.45(V)

Therefore, the Ve system is about 1.5V higher than the unconfigured diode. In addition, the charging current after the constant current charging of 30 mA is also reduced to about 47.5 V, and the influence of the output resistance is also small, and the improvement can be predicted as shown by the following calculation formula.

I=(Vc-Vd-1.5)/Ro

As is apparent from the above description, when the resistor Ri is arranged in parallel with the diode (D), it is predicted that the charging time (charging completion time) can be significantly shortened compared to the case where the diode is not arranged in parallel.

[Embodiment 2]

FIG. 4 is a view showing the charging resistance measuring device of the capacitor shown in FIG. 2 (when the resistor Ri is arranged in parallel with the diode (D)), and the charging operation of the charging operation of the capacitor due to the constant current is measured. Chart of voltage changes.

The conditions for measuring the voltage change are the same as those of the data of Fig. 3, as shown below.

Charging voltage: 50V, charging current: 30mA, charging time: 1 second, input resistance: 1kΩ, measuring object capacitor (DUT): 10μF

4, when the diode (D) is arranged in parallel with the resistor Ri, it can be confirmed that the constant current charging end voltage is higher than that of FIG. 3, and the charging voltage after the constant current charging is completed is also maintained high.

Therefore, in the insulation resistance measuring device of the capacitor shown in FIG. 2 (having a structure in which the resistor Ri is arranged in parallel with the diode (D)), the diode is not arranged in parallel with the resistor Ri (D). In the case of the condition, it can be confirmed that the charging completion time is shortened. Furthermore, comparing Figure 3 with Figure 4, charging is complete The time is shortened by about 16 milliseconds.

Claims (3)

An insulation resistance measuring device for a capacitor includes: a constant voltage constant current supply circuit; and a measurement terminal that is in contact with an electrode connected to one of the capacitors to be measured by the constant voltage constant current supply circuit, and is connected to the measurement a measurement terminal disposed to contact the other electrode of the capacitor of the terminal, a resistor Ri connected to the measurement terminal, and a resistor Ri connected to the resistor Ri, and including an operational amplifier and an inverting input terminal and an output terminal connected to the operational amplifier A current-voltage conversion circuit between the resistors, and an insulation resistance measuring device of the capacitor connected to the voltage measuring device on the output side of the current-voltage conversion circuit, characterized in that the output side of the operational amplifier of the current-voltage conversion circuit a wiring portion, connected in series and arranged in opposite directions, one of which is aligned with the nano-diode, the nano-polar body is connected to the ground, and the resistor connected to the ground is connected, and the resistor is connected to the ground and the resistor is connected to the ground. Between the wiring portion and the input side wiring portion of the aforementioned operational amplifier, by parallel and phase One of the mutually opposite configurations is connected to the diode, and further, the diode is connected in parallel to the resistor Ri. The insulation resistance measuring device for a capacitor according to the first aspect of the invention, wherein the constant voltage constant current supply circuit includes a constant voltage constant current power source and an equivalent output resistance connected to the power source. An insulation resistance measuring device for a capacitor according to the first or second aspect of the patent application, wherein The capacitor is a wafer capacitor.