JP2019212858A - Deterioration degree measuring method for electrolytic capacitor and degradation degree measuring device for electrolytic capacitor - Google Patents

Abstract

To provide a deterioration degree measuring device capable of easily measuring the deterioration degree of an electrolytic capacitor mounted on a printed circuit board.SOLUTION: A deterioration degree measuring device measures the degree of deterioration of an electrolytic capacitor 2 mounted on a printed circuit board 20. A loop antenna 1 formed by wrapping an insulated wire around the electrolytic capacitor 2 serves as a detection unit that detects, as a voltage, radiation noise 2n accompanying a ripple current generated when the printed circuit board 20 of the electrolytic capacitor 2 mounted on the printed circuit board 20 is energized. The detected voltage is measured by a voltage measuring device 3 via a passive probe 3p. Further, when the voltage at the time of the increase in the radiation noise 2n is visualized with the voltage measuring device 3, it becomes possible to determine the degree of deterioration of the electrolytic capacitor 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrolytic capacitor deterioration degree measuring method and an electrolytic capacitor deterioration degree measuring apparatus for measuring the deterioration degree of an electrolytic capacitor mounted on a printed circuit board.

  Conventionally, as a method for measuring the degree of deterioration of an electrolytic capacitor, there is an electrolytic capacitor life detection device that displays the replacement time of an electrolytic capacitor so as to be an appropriate time determined by its life (see, for example, Patent Document 1). .

JP-A-7-222436

  In the technique according to Patent Document 1 described above, a current detecting Hall element is connected to a terminal of an electrolytic capacitor in terms of configuration, and a ripple voltage or a ripple current during charging / discharging of the electrolytic capacitor is measured. Then, the deterioration degree is determined depending on whether the value of the ripple voltage or the ripple current has reached the determination level.

  Here, it is assumed that the ripple voltage or the ripple current is measured in a state where the electrolytic capacitor is mounted on the printed board. In this case, the current detection Hall element needs to be mounted on the printed circuit board together with the electrolytic capacitor in advance, or connected to the terminal of the electrolytic capacitor later.

  However, when the current detection Hall element is mounted on the printed circuit board together with the electrolytic capacitor in advance as in the former case, the current detection Hall element must be mounted on all the electrolytic capacitors on the printed circuit board to be measured. become. For this reason, there are problems that the number of parts of the device on the printed circuit board increases and the mounting area also increases.

  Also, as in the latter case, when the current detection Hall element is connected to the terminal of the electrolytic capacitor later, the current detection Hall element is connected if the electrolytic capacitor is soldered to the printed circuit board in a standing state. It becomes difficult to do. The reason is that when the current detection Hall element is connected to the terminal of the electrolytic capacitor, the terminal of the electrolytic capacitor may be detached, or the position may be shifted to cause a contact failure.

  The present invention has been made to solve such problems, and a method for measuring the degree of deterioration of an electrolytic capacitor and a method for measuring the degree of deterioration of an electrolytic capacitor that can easily measure the degree of deterioration of an electrolytic capacitor mounted on a printed board. An object is to provide an apparatus.

  In order to achieve the above object, the degradation measuring method for an electrolytic capacitor of the present invention is a method for measuring the degradation of an electrolytic capacitor mounted on a printed circuit board. A first step of detecting radiation noise accompanying the ripple current as a voltage, a second step of measuring the voltage, and a third step of determining the degree of deterioration of the electrolytic capacitor based on the voltage when the radiation noise increases And having.

  In order to achieve the above object, the degradation measuring apparatus for electrolytic capacitors according to the present invention is a detection that detects radiation noise associated with a ripple current generated as a voltage when an electrolytic capacitor mounted on a printed circuit board is energized as a voltage. And a voltage measurement unit that measures the voltage detected by the detection unit, and a deterioration degree determination unit that determines the degree of deterioration of the electrolytic capacitor based on the voltage when the radiation noise increases.

  According to the present invention, the degree of deterioration of the electrolytic capacitor mounted on the printed circuit board can be easily measured by the above method or configuration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of an electrolytic capacitor deterioration degree measuring apparatus shown to explain an electrolytic capacitor deterioration degree measuring method according to Embodiment 1 of the present invention. It is a flowchart which shows the correlation of the various characteristics relevant to deterioration of the electrolytic capacitor used as the measuring object of the degradation measuring apparatus for electrolytic capacitors shown in FIG. It is the figure which illustrated the internal circuit of the printed circuit board which mounted the electrolytic capacitor demonstrated in FIG. It is a top view which shows the external appearance structure of the printed circuit board demonstrated in FIG. It is a side view which shows the external appearance structure of the printed circuit board demonstrated in FIG. It is a schematic diagram which shows the specific example of the deterioration degree measurement of the electrolytic capacitor mounted in the printed circuit board by the deterioration degree measuring apparatus for electrolytic capacitors shown in FIG. It is the table | surface which illustrated the result which concerns on the degradation degree measurement demonstrated in FIG. It is a characteristic view which shows the relationship of the loop antenna voltage with respect to the equivalent series resistance of the electrolytic capacitor contained in FIG. FIG. 8 is a characteristic diagram showing the relationship of the base drive circuit voltage with respect to the equivalent series resistance of the electrolytic capacitor included in FIG. 7 including the limit range of measured values. It is a characteristic view which shows the relationship of the loop antenna voltage with respect to the equivalent series resistance of the electrolytic capacitor contained in FIG. It is a schematic block diagram of the degradation degree measuring apparatus for electrolytic capacitors which concerns on Embodiment 2 of this invention.

  Hereinafter, several embodiments of the electrolytic capacitor deterioration degree measuring method (hereinafter referred to as a deterioration degree measuring method) and the electrolytic capacitor deterioration degree measuring apparatus (hereinafter referred to as a deterioration degree measuring apparatus) of the present invention will be described. This will be described in detail with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram of a deterioration degree measuring apparatus shown for explaining a deterioration degree measuring method according to Embodiment 1 of the present invention.

  Referring to FIG. 1, this deterioration degree measuring apparatus measures the deterioration degree of the electrolytic capacitor 2 mounted on the printed circuit board 20. The degradation degree measuring apparatus includes a detection unit that detects, as a voltage, radiation noise 2n that accompanies a ripple current 2c that occurs when the printed circuit board 20 on which the electrolytic capacitor 2 is mounted is energized. This detector corresponds to a loop antenna 1 formed by circulating an insulated wire around the electrolytic capacitor 2.

  One end of the loop antenna 1 on the electrolytic capacitor 2 side is not connected to anything, and the other end of the loop antenna 1 is connected to the voltage measuring device 3 via a passive probe 3p. The passive probe 3p and the voltage measuring device 3 function as a voltage measurement unit that measures a voltage, and also function as a deterioration degree determination unit that determines the deterioration degree of the electrolytic capacitor 2 based on the voltage when the radiation noise 2n increases.

  That is, in this degradation degree measuring apparatus, when a ripple current 2c flows through the electrolytic capacitor 2 in a state where the printed circuit board 20 is energized, radiation noise 2n is generated from the electrolytic capacitor 2 due to electromagnetic induction. This radiation noise 2n is detected as a voltage by the loop antenna 1, and the detected voltage is measured by the voltage measuring device 3 via the passive probe 3p. Furthermore, by visualizing the voltage when the radiation noise 2n increases with the voltage measuring device 3, it is possible to determine the degree of deterioration of the electrolytic capacitor 2. This means that when the voltage when the radiation noise 2n increases is visualized by the voltage measuring device 3, the degree of deterioration of the electrolytic capacitor 2 can be determined based on the voltage waveform.

  FIG. 2 is a flowchart showing a correlation between various characteristics related to deterioration of the electrolytic capacitor 2 to be measured by the deterioration degree measuring apparatus.

  Referring to FIG. 2, generally, when the degradation F1 of the electrolytic capacitor 2 proceeds, the equivalent series resistance (ESR) increases F2, and further increases the ripple current 2c F3. Along with the increase F3 of the ripple current 2c, an increase F4 of the radiation noise 2n from the electrolytic capacitor 2 also occurs. Therefore, it correlates with the deterioration F1 of the electrolytic capacitor 2 and reaches an increase F4 of the radiation noise 2n. However, the equivalent series resistance of the electrolytic capacitor 2 here cannot be measured accurately when the electrolytic capacitor 2 is mounted on the printed circuit board 20.

  The processing function of the deterioration degree measuring apparatus described above can be technically translated as a deterioration degree measuring method. In this case, the deterioration degree measuring method includes the following steps when measuring the deterioration degree of the electrolytic capacitor 2 mounted on the printed circuit board 20. The first step is to detect the radiation noise 2n accompanying the ripple current of the electrolytic capacitor 2 that is generated when the printed circuit board 20 is energized as a voltage. The second step is to measure the voltage. The third step is to determine the degree of deterioration of the electrolytic capacitor 2 based on the voltage when the radiation noise 2n increases.

  FIG. 3 is a diagram illustrating an internal circuit of the printed circuit board 20 on which the electrolytic capacitor 2 to be measured by the degradation degree measuring apparatus is mounted.

  Referring to FIG. 3, this printed circuit board 20 includes a power input connector 22, a primary circuit 23 connected to the primary winding of the transformer T, and a base drive circuit 24 connected to the secondary winding of the transformer T. The control power supply circuit 25 and the output connector 26 are mounted.

  In the printed circuit board 20, the connector 22 (CN1) has three pins of input terminals, and the DC voltage DC100V from the DC power supply 21 is applied to the two pins. However, the primary-side power supply may be an AC power supply, in which case a three-phase AC voltage AC100V is applied. The primary circuit 23 includes capacitors C1, C3, and C4 in addition to the capacitor C2 in the region that forms the electrolytic capacitor 2, and includes a plurality of diodes and resistors, and these devices are connected by a transistor Tr. The

  The base drive circuit 24 outputs the 12V base drive signal transformed by the transformer T to the base terminal of the power semiconductor module forming the external inverter device through the connector 26 (CN2). The control power supply circuit 25 is a power supply voltage source of ± 15 V transformed by the transformer T.

  That is, in the printed circuit board 20, the primary circuit 23 is formed as a self-excited flyback converter, and cooperates with the transformer T to make the base drive circuit 24 a 12V power supply voltage source and a control power supply circuit. 25 is a power supply voltage source of ± 15V. The base drive circuit 24 and the control power supply circuit 25 constitute a secondary circuit.

  Here, the electrolytic capacitor 2 to be measured is charged while the transistor Tr is off. Further, the electrolytic capacitor 2 is in a discharged state during the period from when the transistor Tr is turned off to when the transistor Tr is turned on and from the time when the transistor Tr is turned on. The electrolytic capacitor 2 used in the primary side circuit 23 has an on / off cycle of the transistor Tr of about 30 KHz, and is frequently charged and discharged. For this reason, the progress of the deterioration becomes faster compared to general smoothing applications.

  The following describes the test results of the deterioration degree measurement performed on the electrolytic capacitors 2 of the five printed circuit boards 20 that are actually incorporated and used in an electrical product.

FIG. 4 is a plan view showing an external configuration of the printed circuit board 20 described in FIG. FIG. 5 is a side view showing an external configuration of the same printed circuit board 20. FIG. 6 is a schematic diagram illustrating a specific example of measurement of the degree of deterioration of the electrolytic capacitor 2 mounted on the printed circuit board 20 by the deterioration degree measuring apparatus described with reference to FIG. However, the electrolytic capacitor 2 mounted on the printed circuit board 20 is assumed to be a component having an electric capacity of 33 uF and a withstand voltage of 50V. Moreover, the loop antenna 1 attached to the electrolytic capacitor 2 has a form in which a copper wire with an insulation coating having a cross-sectional area of 2 mm ² is wound five times.

  Referring to FIG. 6, in this degradation degree measuring apparatus, nothing is connected to one end of the loop antenna 1 on the electrolytic capacitor 2 side, and the other end is, for example, a passive probe 3p made of TPP0500B. Is connected. For example, an oscilloscope made by MDO4054B-3 was used as the voltage measuring device 3 connected to the passive probe 3p. The oscilloscope was set to the waveform measurement mode, and the degree of deterioration of the electrolytic capacitor 2 was measured under conditions of a measurement range of 5 V / div and 20 msec.

  Specifically, the content of the measurement of the deterioration degree of the electrolytic capacitor 2 was applied with a DC voltage DC100V from the connector 22 to each electrolytic capacitor 2 of the five printed boards 20 as shown in FIG. Then, the loop antenna voltage of the voltage obtained from the loop antenna 1 was measured by the degradation degree measuring apparatus described with reference to FIG. 6, and the base drive circuit voltage in the base drive circuit 24 was measured.

  Thereafter, the electrolytic capacitor 2 was removed from the printed circuit board 20, and the equivalent series resistance of the electrolytic capacitor 2 alone was measured. Here, the equivalent series resistance of the electrolytic capacitor 2 cannot be measured accurately if the electrolytic capacitor 2 is mounted on the printed circuit board 20. For this reason, after measuring the loop antenna voltage and the base drive circuit voltage, the electrolytic capacitor 2 was removed from the printed circuit board 20, and the equivalent series resistance was measured.

  FIG. 7 is a table illustrating the results relating to the measurement of the degree of deterioration. With reference to FIG. 1, the loop antenna voltage (Vrms) was 7.30, the base drive circuit voltage (V) was 12.37, and the equivalent series resistance (Ω) was 0.86. No. of the test printed circuit board 20 2, the loop antenna voltage (Vrms) was 7.40, the base drive circuit voltage (V) was 12.38, and the equivalent series resistance (Ω) was 0.92.

  No. of the test printed circuit board 20 3, the loop antenna voltage (Vrms) was 7.50, the base drive circuit voltage (V) was 12.40, and the equivalent series resistance (Ω) was 1.03. No. of the test printed circuit board 20 4, the loop antenna voltage (Vrms) was 8.00, the base drive circuit voltage (V) was 12.49, and the equivalent series resistance (Ω) was 2.55. No. of the test printed circuit board 20 5, the loop antenna voltage (Vrms) was 8.30, the base drive circuit voltage (V) was 12.73, and the equivalent series resistance (Ω) was 4.80.

  FIG. 8 is a characteristic diagram showing the relationship of the loop antenna voltage (Vrms) with respect to the equivalent series resistance (Ω) of the electrolytic capacitor 2 included in FIG. That is, FIG. 8 shows a graph of characteristics in which the horizontal axis represents the equivalent series resistance (Ω) of the electrolytic capacitor 2 and the vertical axis represents the loop antenna voltage (Vrms) from the result of the degradation degree measurement shown in FIG. .

  From the characteristics of FIG. 8, it can be confirmed that the loop antenna voltage increases as the equivalent series resistance increases. Here, the solid line of the graph is a line connecting the actual measurement values, and the dotted line indicates an estimated value line that is assumed to be an extension thereof.

  FIG. 9 is a characteristic diagram showing the relationship of the base drive circuit voltage (V) to the equivalent series resistance (Ω) of the electrolytic capacitor 2 included in FIG. That is, FIG. 9 is a characteristic obtained by plotting the equivalent series resistance (Ω) of the electrolytic capacitor 2 on the horizontal axis and the base drive circuit voltage (V) in the base drive circuit 24 on the vertical axis from the result of the degradation degree measurement shown in FIG. The graph is shown.

  From the characteristics of FIG. 9, it can be confirmed that the base drive circuit voltage increases as the equivalent series resistance increases. Here, the solid line of the graph is a line connecting the actual measurement values, and the dotted line indicates an estimated value line that is assumed to be an extension thereof.

  Next, the limit range of the actual measurement value in FIG. 9 will be described. In the circuit of the printed circuit board 20 on which the deterioration degree measurement test is performed, the equivalent series resistance increases as the electrolytic capacitor 2 progresses, and the on-time of the transistor Tr becomes longer. As a result, the base drive circuit voltage increases. Here, in the circuit of the printed circuit board 20, the base drive circuit voltage in the base drive circuit 24 is 12V. In order to operate the base drive circuit 24 normally, it is necessary to suppress the base drive circuit voltage to less than 15 V, which is the limit voltage of the operating conditions.

  Referring to FIG. 9, the base drive circuit voltages of the five printed circuit boards 20 subjected to the deterioration degree measurement test are all less than 15 V, and satisfy the operating condition limit voltage. However, if the printed circuit board 20 is continuously used for a longer period and the equivalent series resistance of the electrolytic capacitor 2 rises to 15Ω, the base drive circuit voltage becomes 15V. This is the limit range of the actual measurement values shown in FIG.

  Under such conditions, the base drive circuit 24 cannot operate normally. That is, it can be said that the equivalent series resistance = 15Ω of the electrolytic capacitor 2 is the limiting resistance in the circuit of the printed circuit board 20. In other words, since the base drive circuit 24 exceeds the rating when the base drive circuit voltage is 15 V, this time may be used as the life determination point.

  FIG. 10 is a characteristic diagram showing the relationship of the loop antenna voltage (Vrms) to the equivalent series resistance (Ω) of the electrolytic capacitor 2 included in FIG. That is, FIG. 10 shows the limit range of the actually measured value with respect to FIG. 8 on the basis of the equivalent series resistance = 15Ω.

  Referring to FIG. 10, when the equivalent series resistance of the electrolytic capacitor 2 is 15Ω and the base drive circuit voltage is 15V, the loop antenna voltage = 9V. This loop antenna voltage = 9V can also be regarded as a limiting voltage.

  Therefore, in the circuit of the printed circuit board 20, when the deterioration level measurement device of FIG. 6 is used to measure the deterioration level of the electrolytic capacitor 2, it is determined that the printed circuit board 20 can be used when the loop antenna voltage is less than 9V. it can. Further, when the loop antenna voltage is 9 V or more, it can be determined that the printed circuit board 20 cannot be used. Furthermore, even if the loop antenna voltage is less than 9V, it can be determined that it is time to replace the printed circuit board 20 if it is close to 9V.

  The processing function of the deterioration degree measuring apparatus described above can be technically translated as a deterioration degree measuring method. In this case, the deterioration degree measuring method includes the following steps when measuring the deterioration degree of the electrolytic capacitor 2 mounted on the printed circuit board 20. In the fourth step, the equivalent series resistance of the electrolytic capacitor 2 removed from the printed circuit board 20 is measured.

  In the fifth step, the deterioration degree of the electrolytic capacitor 2 mounted on the printed circuit board 20 is determined based on the voltage and the equivalent series resistance obtained after executing the second step and the fourth step a plurality of times. Estimate the limiting voltage. Therefore, in the previous third step, the degree of deterioration of the electrolytic capacitor 2 is determined according to the magnitude of the difference value as a result of comparing the voltage and the limit voltage.

Embodiment 2. FIG.
FIG. 11 is a schematic configuration diagram of a deterioration degree measuring apparatus according to Embodiment 2 of the present invention.

  The deterioration degree measuring apparatus according to the second embodiment is different from the structure of the first embodiment in that the functions of the voltage measuring unit and the deterioration degree determining unit are changed to the deterioration degree determining unit 10 of the device circuit configuration. . Further, the loop antenna 1 is circulated around the electrolytic capacitor 2 mounted on the printed circuit board 20, and one end portion of the loop antenna 1 is not connected to anything, and the other end portion is connected to the deterioration degree determination unit 10. .

  The deterioration degree determination unit 10 includes a full-wave rectification circuit 11, a smoothing circuit 12, a limiting voltage circuit 13, a comparator 14, and a notification unit 15.

  The full-wave rectifier circuit 11 is connected to the other end of the loop antenna 1 and full-wave rectifies the voltage detected by the loop antenna 1. The smoothing circuit 12 smoothes the voltage rectified by the full-wave rectifying circuit 11 and then applies the voltage to the positive side of the comparator 14. The full-wave rectifier circuit 11 and the smoothing circuit 12 can be regarded as passively having a function as a voltage measuring unit. The limit voltage circuit 13 outputs a predetermined limit voltage to the negative electrode side of the comparator 14. As this limiting voltage, the limiting voltage of the loop antenna voltage = 9 V described in the first embodiment is used.

  The comparator 14 compares the output voltage of the smoothing circuit 12 with the limit voltage output from the limit voltage circuit 13. The notification unit 15 notifies the output of the comparator 14. The notification unit 15 here includes an LED (light emitting diode) 16 as a light emitting unit connected to the output side of the comparator 14. Thereby, if the lighting condition of LED16 is confirmed, it can be confirmed easily at a glance whether the degradation degree of the electrolytic capacitor 2 exceeded the limit voltage.

  Instead of the LED 16 of the notification unit 15, a buzzer as a sound generation unit connected to the output side of the comparator 14 may be provided in the notification unit 15. For example, when attaching the deterioration measuring apparatus according to the second embodiment to the printed circuit board 20 incorporated in an electric product, when the LED 16 is difficult to visually recognize, the deterioration degree of the electrolytic capacitor 2 is indicated as the notification unit 15. It is preferable to provide a buzzer that can recognize by sound whether or not the limit voltage has been exceeded. Of course, both of the light emitting unit and the sound generating unit may be provided as the notification unit 15.

  In the degradation level measuring apparatus according to the second embodiment, the limiting voltage set in the limiting voltage circuit 13 is set to 9V when performing the degradation level measurement test of the electrolytic capacitor 2 mounted on the printed circuit board 20. Thus, even when the printed circuit board 20 is incorporated in an electrical product, the loop antenna 1 is attached to the electrolytic capacitor 2, and the deterioration degree determination unit 10 can easily determine the deterioration degree of the electrolytic capacitor 2. Can do.

  In the deterioration degree measuring apparatus according to each embodiment, the loop antenna voltage = 9 V is set as a limiting voltage for measuring the deterioration degree of the electrolytic capacitor 2. However, this is merely an example, and a limit voltage for measuring the degree of deterioration of the electrolytic capacitor 2 may be set according to the usage conditions of the target printed circuit board 20.

  In each embodiment described above, the measurement of the degree of deterioration of the electrolytic capacitor 2 in which the electrolytic capacitor 2 is mounted on the printed circuit board 20 has been described. However, the present invention is similarly applied to the electrolytic capacitor 2 that is not mounted on the printed circuit board 20 as long as the radiation noise 2n accompanying the ripple current of the electrolytic capacitor 2 can be detected as a voltage. it can.

  1 loop antenna, 2 electrolytic capacitor, 2c ripple current, 2n radiation noise, 3 voltage measuring instrument, 3p passive probe, 10 degradation degree determination unit, 11 full-wave rectifier circuit, 12 smoothing circuit, 13 limiting voltage circuit, 14 comparator, DESCRIPTION OF SYMBOLS 15 Notification part, 16 LED, 20 Printed circuit board, 21 DC power supply, 22, 26 Connector, 23 Primary side circuit, 24 Base drive circuit, 25 Control power supply circuit, T transformer, Tr transistor.

Claims (7)

A method for measuring the degree of deterioration of an electrolytic capacitor mounted on a printed circuit board,
A first step of detecting, as a voltage, radiation noise associated with a ripple current of the electrolytic capacitor that is generated when the printed circuit board is energized;
A second step of measuring the voltage;
A third step of determining the degree of deterioration of the electrolytic capacitor based on the voltage at the time of increase of the radiation noise;
A method for measuring the degree of deterioration of an electrolytic capacitor having: A fourth step of measuring an equivalent series resistance of the electrolytic capacitor removed from the printed circuit board;
Based on the voltage obtained after executing the second step and the fourth step a plurality of times and the equivalent series resistance, a limit voltage of the deterioration degree of the electrolytic capacitor mounted on the printed circuit board is estimated. And a fifth step to
The method for measuring a degree of deterioration of an electrolytic capacitor according to claim 1, wherein the third step determines a degree of deterioration of the electrolytic capacitor according to a difference value as a result of comparing the voltage and the limit voltage. A detection unit for detecting, as a voltage, radiation noise associated with a ripple current generated in an energized state of the printed circuit board of the electrolytic capacitor mounted on the printed circuit board;
A voltage measurement unit for measuring the voltage detected by the detection unit;
Based on the voltage at the time of increase of the radiation noise, a deterioration degree determination unit that determines the deterioration degree of the electrolytic capacitor;
An electrolytic capacitor deterioration degree measuring apparatus comprising: The deterioration degree determination unit
A full-wave rectifier circuit connected to the detector and full-wave rectifying the voltage detected by the detector;
A smoothing circuit that smoothes the voltage that has been full-wave rectified by the full-wave rectifier circuit;
A limiting voltage circuit for outputting a predetermined limiting voltage;
A comparator for comparing the output voltage of the smoothing circuit with the limit voltage;
A notification unit for reporting the output of the comparator;
The deterioration measuring apparatus for electrolytic capacitors according to claim 3, comprising: The deterioration measuring apparatus for electrolytic capacitors according to claim 4, wherein the notification unit includes a light emitting unit connected to an output side of the comparator. The degradation degree measuring apparatus for electrolytic capacitors according to claim 4 or 5, wherein the notification unit includes a sound generation unit connected to an output side of the comparator. The degradation degree measuring apparatus for electrolytic capacitors according to any one of claims 3 to 6, wherein the detection unit is a loop antenna formed by surrounding an insulated wire around the electrolytic capacitor.

Images