JPH04225174A - Electrolytic capacitor reverse connection detection device - Google Patents

Abstract

PURPOSE:To improve work efficiency by detecting electrically the inverse connection of an electrolytic capacitor without visual observation. CONSTITUTION:A constant voltage is applied to the parts to become a positive and negative electrodes of an electrolytic capacitor C in a noise filter X connected to one end of a power source wire among a set of electric wires of the wire harness for car audio, etc., from a constant voltage source 13, and a current is applied to the electrolytic capacitor C through a resistance 11 for current-voltage conversion. The potential difference of both the ends of the resistance 11 for current-voltage conversion after a constant time is compared with a reference value in a comparison measure 14, and when the difference is larger than the reference value, it is detected that the electrolytic capacitor is made the inverse connection. To the electrolytic capacitor, an enough current can be sent and the voltage of 40 to 75 percent of that rated voltage without breaking down by detection is applied.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor reverse connection detection device for detecting reverse connection of an electrolytic capacitor incorporated in a circuit.

0002

2. Description of the Related Art Recently, in wire assemblies such as wire harnesses for car audio, a noise filter has been connected to one end of a power line in the wire harness to prevent power supply noise. As shown in the circuit diagram of FIG. 9, the noise filter is connected between an inductance coil L inserted in series with a power supply line 1, one end of this inductance coil L on the power supply (battery side) side, and a ground line 2. It is composed of an electrolytic capacitor C. Since the electrolytic capacitor C has polarity, that is, directionality, if an erroneous connection occurs in which the electrolytic capacitor C is not connected as specified, desired filter characteristics cannot be obtained.

[0003] Therefore, in this type of noise filter, FIG.
0, the power supply line 1 and the ground line 2 electrically connected to the inductance coil L and electrolytic capacitor C placed on the substrate 3 are formed with different colored electric wires, and these electric wires 1, 2 is wired along the edge of the electrolytic capacitor C on the board 3 so as to sandwich it, and the electrolytic capacitor C is connected to the board 3 using the wires routed along the edge as a guide. There is. Specifically, a mark M consisting of a white line is attached to the outer circumferential surface of the electrolytic capacitor C to indicate its ground terminal. By electrically connecting the circuit board 3 to the substrate 3, the electrolytic capacitor C can be connected as instructed.

However, even if the connection direction of the electrolytic capacitor C on the substrate 3 is specified in this way, an incorrect connection as shown in FIG. 11 may be made due to operator error. For this reason, as shown in FIG. 12, the direction of the white line mark M is visually inspected before it is finally housed in the filter case 4 shown by the dotted line and completed as a noise filter.

[0005]

[Problems to be Solved by the Invention] When visually inspecting the reverse connection of an electrolytic capacitor as described above, it is necessary that the electrolytic capacitor be visible from the outside, and the inspection time is during the manufacturing process of the noise filter. This poses a problem in that the process of assembling the noise filter is restricted and work efficiency is reduced.

Therefore, in view of the above-mentioned conventional problems, the present invention provides an electrolytic capacitor reverse connection detection device that is capable of improving work efficiency by electrically detecting the reverse connection of an electrolytic capacitor without visual inspection. The challenge is to provide the following.

[0007]

[Means for Solving the Problems] In order to solve the above problems, an electrolytic capacitor reverse connection detection device according to the present invention is an electrolytic capacitor reverse connection detection device for detecting a reverse connection of an electrolytic capacitor incorporated in a circuit. , the first part to which the part in the circuit that should be the positive pole of the electrolytic capacitor is connected
an electrolytic capacitor connection part having a terminal and a second terminal to which a part in the circuit that is to be the ground and the negative pole of the electrolytic capacitor is connected, and an electrolytic capacitor connection part in series between the first terminal and a constant voltage source. a current-voltage conversion resistor connected to the electrolytic capacitor that generates a voltage corresponding to the current flowing through the electrolytic capacitor; detection means for detecting reverse connection of the electrolytic capacitor based on the output of the comparison means after a predetermined period of time after the voltage from the constant voltage source is applied, the detection means detecting the reverse connection of the electrolytic capacitor; The device is characterized in that a reverse connection is detected based on the output of the comparing means when the magnitude of the potential difference between both ends is larger than a predetermined value.

Further, the electrolytic capacitor reverse connection detection device according to the present invention is characterized in that the constant voltage source outputs a voltage that applies a voltage of 40 to 75% of the rated voltage to the electrolytic capacitor. .

Furthermore, the electrolytic capacitor reverse connection detection device according to the present invention is such that the electrolytic capacitor is incorporated in a noise filter connected to one end of a power line in a wire assembly such as a car audio wire harness. It is characterized by being something.

0010

[Operation] In the above configuration, the part of the circuit that should be the positive pole of the electrolytic capacitor and the part of the circuit that should be the negative pole are connected to predetermined terminals, and a constant voltage is supplied from a constant voltage source for current-voltage conversion. Current flows through the electrolytic capacitor through the resistor. At this time, the comparing means compares the magnitude of the potential difference between both ends of the current-voltage conversion resistor with a predetermined value, and after a predetermined period of time after applying the voltage from the constant voltage source, the magnitude of the potential difference between both ends of the current-voltage conversion resistor is The detection means detects that the electrolytic capacitor is reversely connected based on the output of the comparison means when the magnitude of the potential difference is larger than a predetermined value.

[0011] In this way, reverse connection can be detected by the simple operation of applying voltage to a predetermined part, so it can be easily detected even if it is not visible from the outside once it has been incorporated into the circuit. I can do it.

Furthermore, since the voltage applied to the electrolytic capacitor is 40 to 75% of its rated voltage, sufficient measurements can be made and the electrolytic capacitor will not be destroyed during inspection.

Furthermore, since the reverse connection of the electrolytic capacitor is detected by being incorporated into the noise filter connected to one end of the power supply wire in the wire harness for car audio, etc., reverse connection can be detected. This can be done as part of the continuity test for the assembled wires of car audio wiring harnesses, improving work efficiency.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIG. 1 shows a simplified configuration of an embodiment of an electrolytic capacitor reverse connection detection device according to the present invention, which is configured to detect reverse connection of an aluminum electrolytic capacitor incorporated in a noise filter. Before explaining the operation, the principle of the device according to the invention will be explained with reference to FIG.

Generally, in the case of an electrolytic capacitor, when its negative pole is grounded and a voltage is applied to its positive pole, that is, in a correctly connected state, the current flowing through the electrolytic capacitor is as shown by curve A in FIG. As shown, it increases momentarily, then decreases over time, and eventually stops flowing at all. On the other hand, in a reverse connection state where the connection direction is incorrect, the + pole of the electrolytic capacitor is grounded and voltage is applied to the – pole, and the electrolytic capacitor has a voltage as shown by curve B in Figure 2. A large current begins to flow from the beginning, and even after time passes, a larger current continues to flow than in the case of positive connection.

Therefore, the present invention provides an electrolytic capacitor with a predetermined voltage (40 to 70% of the rated voltage of the electrolytic capacitor).
Monitor the magnitude of the current flowing through the electrolytic capacitor after a certain period of time, for example 1 second, after applying a voltage of 5%,
A reverse connection state is detected when the flowing current is larger than a predetermined value, for example, 50 mA.Returning to FIG. 1, the device of the present invention is constructed based on such a principle. explain. 40 to 75% of rated voltage
The voltage is large enough to allow a sufficient current to flow through the electrolytic capacitor to perform measurements, and yet not destroy the electrolytic capacitor when it is connected in reverse, for example.

In FIG. 1, 10a and 10b are a first terminal and a second terminal constituting an electrolytic capacitor connection section 10. The first terminal 10a is connected to one end of the power supply line 1 drawn out from the connection point between one end of the aluminum electrolytic capacitor C in the noise filter One end of the ground wire 2 drawn out from the other end is connected to each end. The first terminal 10a is connected to a constant voltage source 13 via a current-voltage conversion resistor 11 and a normally open switch 12 having a control input.
The second terminal 10b is connected to ground.

The current-voltage converting resistor 11 generates a potential difference between its ends corresponding to the magnitude of the current flowing through it. Both ends of the current-voltage conversion resistor 11 are connected to the input of a differential amplifier 14, and the differential amplifier 14 outputs a voltage corresponding to the input potential difference. The output voltage of the differential amplifier 14 is applied to the − input of a comparator 15 constituting a comparing means, and is compared with a reference voltage of a predetermined value applied to the + input of the comparator 15.

The reference voltage applied to the +input of the comparator 15 is set in advance to a predetermined value by setting the sizes of the voltage dividing resistors 16a and 16b. This predetermined value is the current-voltage conversion resistor 1 when it is positively connected.
It is set to an arbitrary value that is larger than the output voltage of the differential amplifier 14 based on the potential difference between both ends of the signal 1, and smaller than the output voltage of the differential amplifier 14 in the case of reverse connection. As described above, the comparator 15 outputs an L level signal to its output when the voltage applied to its negative input becomes higher than the reference voltage in reverse connection, and the voltage applied to its negative input in positive connection is the reference voltage. When it becomes smaller than the voltage, an H level signal is outputted to its output.

The output signal of the comparator 15 is directly connected to the latch input of the OK latch circuit 16a.
The signals are respectively input to the latch inputs of the input terminals b via the inverters 17. Each latch circuit 16a, 16b takes in and holds a latch input in response to a fall of a load signal, which will be described later, and outputs the held contents.

Reference numeral 18 denotes a start switch for starting the detection operation, and when the start switch 18 is turned on, the first timer circuit 19a outputs its output for a predetermined time t.
A first time signal that maintains an H level for one period is generated. This first time signal is supplied as a control signal to the control input of the normally open switch 12, and is also supplied as a trigger signal to the input of the second timer circuit 19b.

The normally open switch 12 is connected to the first timer circuit 19
is closed (on) while the first time signal from . On the other hand, the second timer circuit 19b maintains its output for a predetermined time t2, for example, 1 second (≦
A second time signal is generated that maintains the H level for a period of time t1), and is supplied as a load signal to each latch circuit 16a, 16b. As a result, the second timer circuit 19b, together with the latch circuits 16a and 16b,
It functions as a detection means for detecting reverse connection of the electrolytic capacitor based on the output of the comparator 15 after a predetermined time t1 has elapsed since the voltage was applied from the constant voltage source 13.

In the above configuration, when the start switch 18 is turned on with the noise filter X having the positively connected electrolytic capacitor C connected to the terminals 10a and 10b as shown in FIG. Circuit 19a generates a first time signal at its output, which turns normally open switch 12 on for a time t1. This switch 1
2, a voltage from the constant voltage source 13 is applied to one end of the current-voltage conversion resistor 11 via the normally open switch 12, and a current flows through the current-voltage conversion resistor 11 and the electrolytic capacitor C to the ground. Further, in response to the rise of the first time signal, the second timer circuit 19b generates a second time signal at the H level for a certain period of time t2 at its output, and sends this to each latch circuit 16a and 16b as a load signal. Supply as.

At this time, the voltages generated across the current-voltage conversion resistor 11 are input to the differential amplifier 14, and a voltage corresponding to the magnitude of the difference between the input voltages is output from the differential amplifier 14. Output. The output voltage of the differential amplifier 14 is proportional to the magnitude of the current flowing through the current-voltage conversion resistor 11. In the case of positive connection, the current flowing through the electrolytic capacitor C is small and decreases with time, so the output voltage of the differential amplifier 14 is compared with the reference voltage in the comparator 15, but it never exceeds the reference voltage. , the output of the comparator 15 remains at H level.

Therefore, at the time when the second time signal falls, the OK latch circuit 16a receives an H level signal;
L-level signals are loaded into the latch circuits 16b, and H-level and L-level signals are output to the outputs of the latch circuits 16a and 16b, respectively, and these output signals cause the electrolytic capacitor C to be in positive connection. can be detected.

On the other hand, a noise filter X having a reversely connected electrolytic capacitor C is connected to terminal 1 as shown in FIG.
0a, 10b, start switch 18
When the capacitor C is turned on, the current flowing through the electrolytic capacitor C is large and does not decrease over time.
Since the output voltage of the differential amplifier 14, which is compared at , is equal to or higher than the reference voltage, the output of the comparator 15 becomes L level.

Therefore, at the time when the second time signal falls, the OK latch circuit 16a and the NG latch circuit 16b are loaded with H level and L level signals, respectively, and the L level signal and H level signal are loaded into the outputs of the OK latch circuit 16a and the NG latch circuit 16b. Level signals are now output, and it is possible to detect that the electrolytic capacitor C is reversely connected by the output signals of the latch circuits 16a and 16b.

3 to 9 are suitable for use in combination with a continuity checker for testing the continuity of assembled wires such as wire harnesses for car audio, and for detecting reverse connections of electrolytic capacitors as part of the continuity test. It is a figure which shows the other Example of an electrolytic capacitor reverse connection detection apparatus. In particular, Figure 3
1 is a simplified perspective view showing a combination of an electrolytic capacitor reverse connection detection device 20 and a continuity checker 30 consisting of a harness inspection table 31 and a main body 32. FIG.

In FIG. 3, the harness inspection table 31 includes:
A car audio wire harness 33 consisting of a plurality of electric wires 33c, one end of which is connected to one connector 33a, and the other end of which is connected to a pin jack or various terminals 33b, is mounted. Further, although not clearly shown in the figure, the harness inspection table 31 also has a connector 33a of a car audio wire harness 33 placed thereon.
There are provided connectors that are interconnected with the terminals 33b, and plugs and terminals that are interconnected with the pin jacks and various terminals 33b, respectively. After the continuity checker 30 is placed on the harness inspection table 31 and the predetermined connections are made as shown in the figure,
A continuity test is performed to check whether each electric wire constituting the car audio wire harness 33 is connected to a predetermined terminal of the connector 33a, and the result is notified by display or the like.

A noise filter X is provided at the other end of the power line 1 in the car audio wire harness 33. Terminals 1a and 2a provided at the ends of the power supply line 1 and the ground line 2 drawn out from the noise filter X, respectively, detect reverse connection of the electrolytic capacitor in the noise filter device 20
The terminals 21a and 21b are respectively connected to terminals 21a and 21b provided at one end of a pair of electric wires 21 drawn out from the terminal.

The electrolytic capacitor reverse connection detection device 20 has a power switch button 23, a start switch button 24, and a reset switch button 2, which are respectively arranged on the panel surface 22.
5. Measuring indicator 26a indicating that measurement is in progress
, an OK indicator 26b indicating that the connection is normal.
, has an NG indicator 26c indicating that the connection is reversed. Then, when it is detected that the electrolytic capacitor is not reversely connected as a result of reverse connection detection, an OK button is displayed to indicate that.
The signal line 27 for outputting a signal and sending it to the main body 32 via the harness inspection table 31 is connected to the harness inspection table 31.
There is a connection between.

FIG. 4 is a circuit diagram showing the main electric circuit configuration inside the electrolytic capacitor reverse connection detection device 20 in FIG. 3, and in the same figure, TM1 to T7 are formed on the circuit board 201 shown in FIG. This is the terminal section. In the terminal part TM1,
A start switch 202, which is turned on when the start switch button 24 is pressed, and a reset switch 203, which is turned on when the reset switch button 25 is pressed, are connected. A signal line 28 for inputting an automatic start signal from a continuity checker is connected to the terminal portion T2 via the harness inspection table 31. The terminal portion T3 is used in the same manner as the electrolytic capacitor connection portion 10 consisting of the first terminal 10a and the second terminal 10b in FIG. 1, and a noise filter X to be inspected for reverse connection is connected to this.

The terminal portion TM4 includes a semi-fixed resistor 204 for setting a reference voltage corresponding to a current value for determining reverse connection, and an electrolytic capacitor C for performing a reverse connection test.
A semi-fixed resistor 205 is connected to set the time period for which current flows. The terminal part TM5 has the above-mentioned indicator 2 that lights up to indicate measurement in progress, OK, and NG.
LEDs 206 to 208 constituting 6a to 26c are connected. A signal line (not shown) for outputting a time signal and a voltage level signal, respectively, is connected to the terminal portion TM6. A signal line 27 for supplying an OK signal to the continuity checker body via the harness test stand 31 and a signal line (not shown) for outputting an NG signal are connected to the terminal portion TM7. Note that an AC 100V outlet 209 is connected to the terminal portion TM8.

210 to 212 are start switches 20
2. A chattering prevention circuit is provided corresponding to the reset switch 203 and the relay contact S1, respectively,
Relay contact S1 is switched by relay R1 which is energized by an automatic start signal input from a continuity checker via signal line 28. In response to turning on the start switch 202, the chattering prevention circuit 210
The chattering prevention circuit 212 outputs an H level start signal to each output in response to switching of the contact S1, and
The chattering prevention circuit 211 is a reset switch 203
In response to turning on, a reset pulse signal is output to its output. A power-on detection circuit 213 outputs a reset pulse signal to its output when detecting power-on.

T1 to T5 are chattering prevention circuits 21
1 and a reset pulse signal from the power-on detection circuit 213, the timer circuit is reset and its output is set to L level. The timer circuit T1 outputs a pulse signal having a relatively short constant time width to its output in response to the rise of the outputs of the chattering prevention circuits 210 and 212. In response to the fall of the pulse signal output from the timer T1, the timer circuit T2 outputs a pulse signal lasting 1 second, and the timer circuit T3 outputs a pulse signal lasting 0.5 seconds to 1 second. Circuit T4 has 3 at its output
Each outputs a pulse signal lasting 00 milliseconds. Further, the timer circuit T5 generates a pulse signal lasting 1.5 seconds to 2 seconds at its output in response to the falling edge of its input. The duration of the pulse signal generated by the timer circuit T3 at its output is used to define the time point at which the current level flowing through the electrolytic capacitor is determined, and is adjusted to zero by adjusting the semi-fixed resistor 205 connected to the terminal section TM3. It is variable in the range of .5 to 1 second.

FF1 to FF3 are D-type flip-flops constituting a latch circuit, and each of these flip-flops FF1 to FF3 is connected to a chattering prevention circuit 2.
It is reset by the rise of the reset pulse signal from 11 and the power-on detection circuit 213, and its output is set to L level, and when its load input falls, it captures the state of its D input and outputs this captured state. do. Note that the flip-flops FF1 and FF2 are the OK latch circuit 16a and the NG latch circuit 16 described above with respect to FIG.
b.

[0037] R2 to R5 are relays, and relay R2
Contacts S2 to S4 of relay R4 are turned on by the energization, and contacts S5 of relay R5 are turned on by the energization.
is switched.

214 is a current-voltage conversion resistor that converts the flowing current into voltage, and is similar to the current-voltage conversion resistor 11 in FIG.
This corresponds to 215 is current-voltage conversion resistor 2
This is a differential amplifier that inputs a potential difference generated between both ends of the differential amplifier 14 when a current flows through the differential amplifier 14, and outputs a voltage corresponding to the magnitude of this potential difference.
This corresponds to A comparator 216 compares the output voltage of the differential amplifier 215 with a reference voltage and outputs the result, and corresponds to the comparator 15 in FIG. 217 is AC1 input from outlet 209
This is a constant voltage source that stabilizes the DC voltage output by a power supply circuit (not shown) based on 00V and outputs a constant voltage. The voltage output by the constant voltage source 217 is set to, for example, 9V when the rated voltage of the electrolytic capacitor is 16V. The reference voltage of the comparator 216 is adjusted by the semi-fixed resistor 205 described above.

The operation of the apparatus whose schematic configuration has been explained above is as follows.
The following description will be made with reference to timing charts of FIGS. 6 to 8 showing the states of each part.

First, normally connected electrolytic capacitor C
When the noise filter X having the noise filter X is connected as shown in FIG. A pulse signal as shown by A in FIG. 6 is generated at its output. This pulse signal A is applied to trigger inputs of timer circuits T2 and T4, timer circuits T2 to T5, and flip-flops FF.
It is applied to the reset inputs of FF1 to FF3. As a result, timer circuits T2 to T5 and flip-flops FF
FF1 to FF3 are reset in response to the rise of the pulse signal A, and their outputs are all set to L level.

Then, when the pulse signal A falls,
In response, timer circuit T2 is triggered to generate a pulse signal lasting 1 second as shown at B in Figure 6, and timer circuit T4 generates a pulse signal lasting 300 milliseconds as shown at D in Figure 6. Occur. Pulse signal B is applied to the trigger inputs of timer circuits T3 and T5, and
Applied to relays R2 and R5. This energizes relays R2 and R5 as shown by I and L in FIG. 6, turning on their contacts S2 and switching their contacts S5. The timer circuit T5 is triggered in response to the rising edge of the pulse signal B and generates a pulse signal as shown by E in FIG. This pulse signal E lights up the LED 206 as a measurement indicator and also energizes the relay R2. On the other hand, pulse signal D is applied to the load input of FF3.

As described above, contact S2 is turned on, and contact S5 is turned on.
By switching the contact S2 from the constant voltage source 217
, current-voltage conversion resistor 214, contact S5 and coil 21
Current flows to ground through 8. As a result, the voltage generated at one end of the coil 218 is inverted, and an L level voltage is applied to the D input of the FF3. And time 3
When the pulse signal D falls after 00 milliseconds, the D input is latched to FF3 in response, but the output of FF3 is as shown in Figure 6.
As shown by H in the figure, it remains at the L level, unchanged from the previous state.

As described above, when a current flows through the current-voltage conversion resistor 214, a potential difference is generated between both ends thereof. This potential difference is input to the differential amplifier 216, and a voltage corresponding to the magnitude of the potential difference is generated at its output, and this voltage is compared with a reference voltage in the comparator 216. The output of the comparator 216 is always held at H level by a pull-up resistor, but does not change unless the output voltage of the differential amplifier 216 becomes higher than the reference voltage.

When the pulse signal B falls one second after the timer circuit T2 is triggered, the relay R5 is deenergized as shown by L in FIG. 6, and its contact S5 becomes as shown in the figure. Upon returning to state, timer circuit T3 is triggered to produce at its output a pulse signal lasting from 0.5 to 1 second as shown at C in FIG. This pulse signal C is applied to the load inputs of flip-flops FF1 and FF2.

By switching the contact S5 as described above, current now flows from the constant voltage source 217 to the ground through the contact S2, the current-voltage conversion resistor 214, and the contact S5. However, since the electrolytic capacitor is positively connected, the current value decreases over time, the output voltage of the differential amplifier 215 does not exceed the reference voltage, and the output of the comparator 216 remains at H level. be. Therefore, the output of flip-flop FF3 held at L level and the comparator 2 held at H level
The output of the NAND circuit 219 inputting the output of 16 is L.
level.

After that, the pulse signal C from the timer circuit T3
When falls, the L level of the output of the NAND circuit 219 is latched into the flip-flop FF2, which is directly input to the D input, and its output becomes the L level, while the L level of the output of the NAND circuit 219 is The H level is latched into the flip-flop FF1, which is inverted and input to the D input, and its output becomes H level. As a result, the LED 207 as an OK indicator is lit, the relay R3 is energized, its contact S3 is turned on, and an OK signal is outputted via the signal line 27.

Next, the operation when the electrolytic capacitors are reversely connected will be explained with reference to the timing chart of FIG. When the connection is positive, the output of the comparator 216 is H.
The operation until the pulse signal C of the output of the timer circuit T3 falls is the same as in the case of the forward connection, except that the output signal C becomes the L level in the case of the reverse connection. When the output of the comparator 216 is at the L level, the output of the NAND circuit 219 is at the H level, and in response to the fall of the pulse signal C, the flip-flops FF1 and FF
2, the L and H levels are respectively latched. Therefore, the LED 208 as an NG indicator is lit, and the relay R4 is energized and its contact S4 is turned on.

Finally, when the start switch 202 is turned on, if the noise filter X is not connected or the electrolytic capacitor is not connected within the noise filter At the time when FF3 falls, the H level is latched in the flip-flop FF3, and the output becomes H as shown by H in FIG.
become the level. Therefore, since the output of the NAND circuit 219 remains at the H level thereafter, the L and H levels are latched in the flip-flops FF1 and FF2, respectively, in response to the fall of the pulse signal C. The LED 208 as an NG indicator is lit, and the relay R4 is energized and its contact S4 is turned on. As a result, relay R5, contact S5, coil 218, and flip-flop FF3 constitute means for detecting disconnection of the electrolytic capacitor as NG in the same way as reverse connection.

Note that since a signal indicating the time during which the pulse signals A and B are output to the outputs of the timer circuit 2 and T3 and a signal indicating the reference voltage level of the comparator 216 are output to the terminal portion TM6, By connecting a display here, the timer circuit T3 can be activated by checking the display on this display.
The time and reference voltage of the comparator can be adjusted.

Further, the continuity checker 30 sends out a start signal through the signal line 28 and then outputs an O signal through the signal line 27.
When the K signal is not input, it can be independently determined that the electrolytic capacitor is reversely connected or not connected. Note that the signal line 27 may be directly connected to the main body 32 without going through the harness inspection table 31.

Furthermore, although the electrolytic capacitor reverse connection detection device 20 shown in FIG. 4 is used in combination with the continuity checker 30, it can also be used alone since it has an independent start switch and indicator. .

[0052]

[Effects of the Invention] As explained above, according to the present invention, reverse connection of electrolytic capacitors in a circuit can be detected by the simple operation of applying voltage to a predetermined portion. Detection can be easily performed even if the circuit is not installed and visible from the outside, and the inspection point is not specified in the circuit manufacturing process, eliminating constraints on the circuit assembly process and improving work efficiency.

Furthermore, since the voltage applied to the electrolytic capacitor is set at 40 to 75% of its rated voltage, sufficient measurements can be made and the electrolytic capacitor will not be destroyed during inspection.

Furthermore, detection of reverse connection of the electrolytic capacitor can be performed as part of the continuity test of the car audio wire harness, improving work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of an electrolytic capacitor reverse connection detection device according to the present invention.

FIG. 2 is a current waveform diagram for explaining the principle of the device of the present invention.

FIG. 3 is a diagram showing another embodiment of the electrolytic capacitor reverse connection detection device of the present invention suitable for use in combination with a wire harness continuity checker.

FIG. 4 is a diagram showing the main circuit configuration of the electrolytic capacitor reverse connection detection device in FIG. 3;

FIG. 5 is a diagram showing a substrate configuration used in the configuration of the circuit shown in FIG. 4;

FIG. 6 is a timing chart showing the state of each part in the circuit of FIG. 4 in the case of positive connection.

FIG. 7 is a timing chart showing the state of each part in the circuit of FIG. 4 in the case of reverse connection.

8 is a timing chart showing the state of each part in the circuit of FIG. 4 when not connected; FIG.

FIG. 9 is a circuit diagram showing a circuit configuration of a noise filter having an electrolytic capacitor.

FIG. 10 is a diagram showing the arrangement of electronic components constituting a noise filter in the case of positive connection.

FIG. 11 is a diagram showing the arrangement of electronic components constituting a noise filter in the case of reverse connection.

FIG. 12 is a perspective view showing the final assembled structure of the noise filter.

[Explanation of symbols]

10 Electrolytic capacitor connection part 1
0a First terminal 10b
Second terminal 11, 214 Current-voltage conversion resistor 13, 217 Constant voltage source 15, 216 Comparator (comparison means) 16a
OK latch circuit 16b
NG latch circuit 19b
Second timer circuit 33 Car audio wire harness X
Noise filter (circuit) C
Electrolytic capacitor FF1, FF2 Flip-flop T2, T3 Timer circuit

Claims (3)

[Claims] Claim 1: In an electrolytic capacitor reverse connection detection device for detecting reverse connection of an electrolytic capacitor incorporated in a circuit, a first terminal to which a part in the circuit that should be the positive pole of the electrolytic capacitor is connected, and a ground terminal. and a second terminal to which a part in the circuit that is to become the negative pole of the electrolytic capacitor is connected, and the electrolytic capacitor is connected in series between the first terminal and a constant voltage source. a current-voltage converting resistor that generates a voltage corresponding to the current flowing in the current-voltage converting resistor, a comparison means for comparing the magnitude of the potential difference between both ends of the current-voltage converting resistor with a predetermined value; detection means for detecting a reverse connection of the electrolytic capacitor based on the output of the comparison means after a predetermined period of time after the voltage of A reverse connection detection device for an electrolytic capacitor, characterized in that a reverse connection is detected based on the output of the comparison means when the difference is larger than a predetermined value. 2. The electrolytic capacitor reverse connection detection device according to claim 1, wherein the constant voltage source outputs a voltage that applies a voltage of 40 to 75% of the rated voltage to the electrolytic capacitor. 3. The electrolytic capacitor according to claim 1, wherein the electrolytic capacitor is incorporated in a noise filter connected to one end of a power line in a wire assembly such as a car audio wire harness. Electrolytic capacitor reverse connection detection device.