CN108957210B - Electrolytic capacitor polarity detection circuit and detection device - Google Patents
Electrolytic capacitor polarity detection circuit and detection device Download PDFInfo
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- CN108957210B CN108957210B CN201810910340.6A CN201810910340A CN108957210B CN 108957210 B CN108957210 B CN 108957210B CN 201810910340 A CN201810910340 A CN 201810910340A CN 108957210 B CN108957210 B CN 108957210B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/64—Testing of capacitors
Abstract
The invention discloses an electrolytic capacitor polarity detection circuit, which comprises a power circuit, a detection circuit, a comparison circuit and a control indication circuit, wherein the detection circuit is used for accessing a capacitor to be detected; the power supply circuit comprises a first voltage division circuit; the detection circuit is coupled with the first voltage division circuit and is connected with the inverting input end of the comparison circuit so as to be compared with the preset voltage of the non-inverting input end of the comparison circuit, and the comparison circuit outputs a level signal; the control indicating circuit is connected with the output end of the comparison circuit, and the working state of the control indicating circuit is controlled by the level signal output by the comparison circuit. The invention also discloses an electrolytic capacitor polarity detection device applying the circuit. The method is applied to detecting whether the capacitor on the circuit board is reversely inserted or not, solves the problem of inaccurate detection, and has the advantages of accurate result, no damage to devices and the like.
Description
Technical Field
The invention relates to the field of capacitance detection, in particular to the field of electrolytic capacitor polarity detection circuits and detection devices.
Background
The electrolytic capacitor is divided into a positive polarity and a negative polarity, polarity reverse insertion may occur when the electrolytic capacitor is integrated on a circuit board, and the polarity reverse insertion of the electrolytic capacitor may cause the reliability reduction and the functional failure of the circuit board. At present, whether the electrolytic capacitor is reversely inserted or not is mainly detected manually or contrastively analyzed by AO equipment, and in addition, the difference of electric leakage between the anode and the cathode and the shell is utilized for detection.
Chinese patent CN202443090U discloses an online capacitance polarity tester. This patent has utilized the different principle of electric leakage between positive negative pole and the shell, gathers and awaits measuring the electric signal of electric capacity, handles through the singlechip, accomplishes the detection to carrying out positive and negative interpolation.
Although the tester can detect the capacitance detection polarity, the leakage difference is utilized to detect, the probe is required to be in contact with the shell, the capacitor shell is possibly damaged, the good contact with the shell is difficult to ensure, and the detection is inaccurate. The tester can only test the capacitor, cannot test the subsequent circuit function, and has low efficiency.
Disclosure of Invention
Aiming at the technical problems of the polarity detection of the electrolytic capacitor, the invention provides the polarity detection circuit of the electrolytic capacitor and the detection device, which have accurate detection results and small environmental influence and can be applied to an FCT device for complete testing.
In order to achieve the purpose, the invention provides the following technical scheme:
an electrolytic capacitor polarity detection circuit, characterized in that: the device comprises a power circuit, a detection circuit, a comparison circuit and a control indication circuit, wherein the detection circuit is used for accessing a capacitor to be detected, the comparison circuit outputs different levels when the capacitor to be detected is inserted positively and reversely, and the control indication circuit is used for controlling the working state of a load in the circuit and indicating;
the power supply circuit comprises a first voltage division circuit, a rectifying circuit and a voltage stabilizing filter circuit; the rectifier circuit is a bridge-type rectifier circuit with four connecting ports, which is formed by annularly connecting four diodes, wherein the port at the connecting position of the anode and the cathode of two diodes is a first output end of the rectifier circuit; the other two diodes are opposite in position, and the port at the connection position of the negative electrode and the negative electrode is a second output end of the rectifying circuit; the other two ports of the bridge type rectifying circuit are respectively a first input end of the rectifying circuit and a second input end of the rectifying circuit;
the detection circuit is coupled with the first voltage division circuit and is connected with the inverting input end of the comparison circuit so as to compare with the preset voltage of the non-inverting input end of the comparison circuit and output a level signal;
the control indicating circuit is connected with the output end of the comparison circuit, and the working state of the control indicating circuit is controlled by the level signal output by the comparison circuit.
As a preference, the first and second liquid crystal compositions are,
the first voltage division circuit comprises a resistor R1 and a resistor R2, a first end of the resistor R2 is connected with the ground wire, and a second end of the resistor R2 is connected with a first end of the resistor R1;
the two ends of the alternating current stabilized voltage supply are connected with a first input end of a rectifying circuit and a second input end of the rectifying circuit of the bridge type rectifying circuit, a first output end of the rectifying circuit is connected with a first end of a resistor R1, and a second output end of the rectifying circuit is connected with a ground wire;
the voltage stabilizing filter circuit comprises a voltage stabilizing chip N101 and a filter capacitor C1, wherein the input end of the voltage stabilizing chip N101 is connected with the first output end of the rectifier circuit, the grounding end of the voltage stabilizing chip N101 is connected with the ground wire, the output end of the voltage stabilizing chip N101 is connected with the positive electrode of the filter capacitor C1, and the negative electrode of the filter capacitor C1 is connected with the ground wire.
Preferably, the comparison circuit comprises a second voltage division circuit, a voltage comparator chip N102, a pull-up resistor R3 and a first protection resistor R4;
the second voltage division circuit comprises a resistor R5 and a resistor R6, the first end of the resistor R5 is connected with the first output end of the rectifying circuit, the second end of the resistor R5 is connected with the first end of the resistor R6, and the second end of the resistor R6 is connected with the ground wire;
the power supply end of a voltage comparator chip N102 is connected with a direct-current power supply, the grounding end of the voltage comparator chip N102 is connected with the ground wire, the non-inverting input end of the voltage comparator chip N102 is connected with the second end of a resistor R5, the inverting input end of the voltage comparator chip N102 is connected with a detection circuit, the output end of the voltage comparator chip N102 is connected with the first end of a first protection resistor R4, and the second end of the first protection resistor R4 is connected with a control indication circuit;
the first end of a pull-up resistor R3 is connected with a power supply, and the second end of a pull-up resistor R3 is connected with the output end of the voltage comparator chip N102.
Preferably, the detection circuit comprises a first tool test needle, a second tool test needle and the electrolytic capacitor CX to be detected; the two ends of the electrolytic capacitor CX to be detected are respectively connected with a first tool test probe detection end and a second tool test probe detection end; the second tool test pin connecting end is connected with the ground wire, and the first tool test pin connecting end is connected with the reverse input end of the voltage comparator chip N102.
Preferably, the control indicating circuit comprises a relay control circuit and an indicating circuit; the relay control circuit comprises a relay K1 and a triode B1 controlled by a voltage comparator chip N102; the indicating circuit comprises a first switch S1 and a second switch S2 which are electrically connected with the relay K1, and an LED indicator lamp V5 connected with the second switch S2.
Preferably, the relay control circuit further comprises a power supply and a second protection resistor R8, a first end of the relay K1 is connected with the power supply, a second end of the relay K1 is connected with a first end of the second protection resistor R8, a second end of the second protection resistor R8 is connected with a collector of the triode B1, and an emitter of the triode B1 is connected with a ground wire; the base electrode of the triode B1 is connected with the voltage comparator chip N102 through a first protection resistor R4;
two ends of a first switch S1 are respectively connected with the connecting end of a first tool test needle and the second end of a resistor R2, two ends of a second switch S2 are respectively connected with an LED indicator lamp V5 and a power supply, and the other end of the LED indicator lamp V5 is connected with a ground wire; the first switch S1 and the second switch S2 are arranged: the first switch S1 and the second switch S2 are opened when the relay K1 is pulled in, and the first switch S1 and the second switch S2 are closed when the relay K1 is released.
Preferably, the relay control circuit further comprises a protection diode V6, a cathode of the protection diode V6 is connected with the first end of the relay K1, and an anode of the protection diode V6 is connected with the second end of the relay K1.
An electrolytic capacitor polarity detection device, characterized in that: the electrolytic capacitor polarity detection circuit further comprises an FCT test frame, a test frame buckle, an FCT test frame power switch, a power plug, a third tool test needle and a fourth tool test needle, wherein the test frame buckle, the FCT test frame power switch, the power plug, the third tool test needle and the fourth tool test needle are arranged on the FCT test frame and used for limiting a circuit board to be tested.
Preferably, the first tool testing needle and the second tool testing needle are respectively connected with two ends of an electrolytic capacitor CX to be tested on the circuit board to be tested, and the third tool testing needle and the fourth tool testing needle are connected with a power supply end of the circuit to be tested.
Preferably, the testing device further comprises a third switch S3, wherein the third switch S3 is electrically connected with the relay K1, and two ends of the third switch S3 are respectively connected with the FCT testing frame and the live wire; the third switch S3 is set to close the third switch S3 when the relay K1 pulls in, and to open the third switch S3 when the relay K1 releases.
The invention has the beneficial effects that: the invention utilizes the coupling of the capacitor to be tested and the rectifying filter circuit, and the output voltage is compared with the preset voltage to finish the test of the capacitor to be tested; when the invention is used for testing the electrolytic capacitor, the influence of the environment is less. The invention accesses the pins at the two ends of the capacitor into the circuit through the probe, and compared with a tester which tests by using the contact of the probe and the shell, the invention ensures good contact and does not damage the capacitor. The invention can also be applied to an FCT device for testing a complete circuit board, and has the advantage of high efficiency.
Drawings
FIG. 1 is a schematic diagram of an electrolytic capacitor polarity detection circuit provided in the present invention;
FIG. 2 is a schematic circuit diagram of an electrolytic capacitor polarity detection device according to the present invention;
fig. 3 is a schematic view of a tooling of the electrolytic capacitor polarity detection device provided by the invention.
Wherein: 1. a power supply circuit; 2. a comparison circuit; 3. a detection circuit; 4. a control indication circuit; 31. a first tooling test pin; 32. a second tool test pin; 51. an FCT test rack; 52. the test frame is buckled; 53. a circuit board to be tested; 54. an FCT test rack power switch; 55. a power plug; 56. a third tool test pin; 57. and a fourth tool test needle.
Detailed Description
Hereinafter, embodiments of the present invention will be further described with reference to the accompanying drawings.
The invention provides an electrolytic capacitor polarity detection circuit and an electrolytic capacitor polarity detection device, which can be used in the field of electrolytic capacitor polarity detection. The invention utilizes the principle that the size of the rectified alternating current is 1.2-1.4 times of the original size of the electrolytic capacitor of the household appliance after the alternating current is rectified by a diode and filtered, and has the advantages of accurate result, less environmental influence, no damage to components and the like.
The polarity detection circuit of the electrolytic capacitor provided by the invention is shown in figure 1 and mainly comprises a power supply circuit 1, a comparison circuit 2, a detection circuit 3 and a control indication circuit 4.
The invention utilizes the principle that the size of alternating current is 1.2-1.4 times of the original size after the alternating current is rectified by a diode and filtered by an electrolytic capacitor, and a corresponding power supply circuit 1 comprises an alternating current stabilized voltage power supply, a rectifying circuit formed by the diode, a voltage division circuit for distributing reasonable voltage for the electrolytic capacitor CX to be detected and a voltage stabilization filter circuit.
The rectifier circuit is a bridge rectifier circuit with four connection ports formed by annularly connecting four diodes, as shown in a power circuit part of fig. 1, wherein two diodes, and a port at the connection position of the positive electrode and the positive electrode is a first output end of the rectifier circuit; the other two diodes are opposite in position, and the port at the connection position of the negative electrode and the negative electrode is a second output end of the rectifying circuit; the other two ports of the bridge type rectifying circuit are respectively a first input end of the rectifying circuit and a second input end of the sorting circuit. Two ends of the alternating current voltage stabilizing circuit are respectively connected with a first input end of the rectifying circuit and a second input end of the rectifying circuit of the bridge type rectifying circuit, so that a first output end of the rectifying circuit and a second output end of the rectifying circuit of the bridge type rectifying circuit output full-waveform direct current voltage. The first output end of the rectifying circuit is connected with other loads to supply power to other loads; the second output end of the rectifying circuit is connected with the ground wire.
As shown in the power circuit portion of fig. 1, the first voltage dividing circuit is composed of a resistor R1 and a resistor R2, the first output terminal of the rectifier circuit is connected to the second terminal of the resistor R1, the first terminal of the resistor R1 is connected to the second terminal of the resistor R2, the first terminal of the resistor R2 is connected to the ground, the resistor R1 and the resistor R2 are connected in series, and the resistance values of the two resistors can be set according to specific voltage division. In this embodiment, the voltage of the ac regulated power supply is set to 12V, the divided voltage of the resistor R2 is set to 5V, and accordingly the resistance of the resistor R1 is set to 4.7K Ω, the resistance of the resistor R2 is set to 3.3K Ω, and the divided voltage of the resistor R2 is 12 × 3.3/(4.7+3.3) ≈ 5V. The voltage of the AC voltage regulator can be set to other values, such as 9V or 36V; the voltage division on the resistor R2 can also be set to be smaller than the voltage value of the regulated power supply, for example, when the regulated power supply is 9V, the voltage division on the resistor R2 can be set to be 3V or 6V; the resistances of the resistor R1 and the resistor R2 are configured according to the voltage of the regulated power supply and the voltage division of the resistor R2.
In any resistor mentioned in the present application, if the resistor is horizontally arranged in the circuit diagram, the first end of the resistor and the second end of the resistor are arranged from left to right in sequence; if the resistor is arranged perpendicular to the horizontal direction in the circuit diagram, the first end of the resistor and the second end of the resistor are arranged from top to bottom in sequence.
As shown in the power circuit part of fig. 1, the voltage stabilizing and filtering circuit part is composed of a voltage stabilizing chip N101 and a filtering capacitor C1, the voltage stabilizing chip N101 in this embodiment is a 7812 three-terminal voltage stabilizing chip, and its three ports are an input terminal, a ground terminal and an output terminal respectively. In fig. 1, an interface 1 of the voltage regulator chip N101 is an input terminal, an interface 2 is a ground terminal, and an interface 3 is an output terminal. The input end of the 7812 three-terminal voltage stabilization chip is connected with the first output end of the rectification circuit, and the output end of the voltage stabilization chip N101 is connected with the anode of the filter capacitor C1; the grounding end of the voltage stabilizing chip N101 is connected with the ground wire, and the negative electrode of the filter capacitor C1 is connected with the ground wire; after being subjected to voltage stabilization and filtration, 12V direct current is obtained. The voltage stabilizing filter circuit and the first voltage dividing circuit are connected in parallel in the power supply circuit.
As shown in fig. 1, the comparison circuit 2 is composed of a voltage comparator chip N102, a pull-up resistor R3, a first protection resistor R4, a resistor R5, and a resistor R6. The first end of the resistor R5 is connected with the output end of the voltage stabilizing chip N101, the second end of the resistor R5 is connected with the first end of the resistor R6, and the second end of the resistor R6 is connected with the ground wire; the resistor R5 and the resistor R6 are connected in series to form a second voltage division circuit, and the second voltage division circuit is connected between the output end of the voltage stabilizing chip N101 and the ground wire; the resistor R5 is connected with the output end of the voltage stabilizing chip N101, and the resistor R6 is connected with the ground wire. In this embodiment, the resistance of the resistor R5 is 5K Ω, the resistance of the resistor R6 is 4.2K Ω, and the divided voltage of the resistor R6 is 12 × 4.2/(5+4.2) ≈ 5.5V. The resistances of the resistor R5 and the resistor R6 may be configured to have other values, such that the voltage division on the resistor R6 is larger than the voltage division on the resistor R2, but smaller than 1.2 times of the voltage division on the resistor R2. For example, in another embodiment, when the regulated voltage is set to 9V, the divided voltage on the resistor R2 can be set to 6V, the resistance of the resistor R5 can be set to 6K Ω, the resistance of the resistor R6 can be set to 2.3K Ω, and the divided voltage on the resistor R6 can be 9 x 6/(6+2.3) ≈ 6.5V
In the present embodiment, the voltage comparator chip N102 employs an LM393 voltage comparator chip, and as shown in the comparison circuit portion in fig. 1, pins 1, 2, 3, 4, and 8 of the voltage comparator chip N102 are selected as an output terminal, an inverting input terminal, a non-inverting input terminal, a ground terminal, and a power supply terminal. The ground terminal of the voltage comparator chip N102 is connected with the ground wire, and the power terminal is connected with the output terminal of the voltage stabilizer in the power circuit to provide 12V direct current working voltage for the voltage comparator chip N102. The second terminal of the resistor R5 is connected to the non-inverting input terminal of the voltage comparator chip N102, and the voltage at the non-inverting input terminal of the voltage comparator chip N102 is divided by the voltage R6, which is 5.5V. When the voltage of the reverse input end of the voltage comparator chip N102 is greater than that of the in-phase input end, the output end of the voltage comparator chip N102 outputs high level; when the voltage of the reverse input end of the voltage comparator chip N102 is smaller than that of the non-reverse input end, the output end of the voltage comparator chip N102 outputs low level. The output end of the voltage comparator chip N102 is connected with the first end of a first protection resistor R4, and the second end of the first protection resistor R4 is connected with the control indication circuit. In addition, the voltage comparator chip N102 must set a pull-up resistor for normal operation. Two ends of the pull-up resistor R3 are respectively connected with the power supply section and the output end of the voltage comparator chip N102, the resistor R3 in the comparison circuit part is used as a pull-up resistor of the voltage comparator chip N102, the resistance value of the pull-up resistor R3 is set to be 1K omega in the embodiment, and the resistance value of the first protection resistor R4 is 1K omega. The pull-up resistor R3 may also be configured to have a resistance of 1.5K Ω or 2K Ω or other values; the first protection resistor R4 may be configured to have a resistance of 1.2K Ω or 2.1K Ω or other values.
As shown in the detection circuit portion of fig. 1, the detection circuit 3 is composed of a first tool testing needle 31, a second tool testing needle 32 and an electrolytic capacitor CX to be detected. The first tooling test needle 31 and the second tooling test needle 32 are used for connecting the electrolytic capacitor CX to be tested to a circuit; the detection end of the first tooling test needle 31 is connected with one end of the electrolytic capacitor CX to be detected, and the wiring end of the first tooling test needle 31 is connected to the second end of the resistor R2 through a first switch S1; the detection end of the second tool test needle 32 is connected with the other end of the electrolytic capacitor CX to be detected, and the wiring end of the second tool test needle 32 is grounded; the electrolytic capacitor CX to be measured and the resistor R2 are in parallel connection in the circuit. The terminal of the second tool testing pin 32 is further connected to the inverting input terminal of the voltage comparator chip N102, and when the second switch S2 is closed, the voltage at the second terminal of the resistor R2 will be used as the input voltage of the inverting input terminal of the voltage comparator chip N102.
When the electrolytic capacitor CX to be detected is positively connected, the negative electrode of the electrolytic capacitor CX to be detected is connected with the detection end of the first tool testing needle 31, and the positive electrode of the electrolytic capacitor CX to be detected is connected with the detection end of the second tool testing needle 32. The positively connected electrolytic capacitor CX to be detected is connected with the resistor R2 in parallel, and under the action of the electrolytic capacitor, the voltage division on the resistor R2 is improved by 1.2-1.4 times and is within the range of 6V-7V; the voltage of the reverse input end of the corresponding voltage comparator chip N102 is in the range of 6V-7V and is greater than 5.5V of the voltage of the same-phase input end, and the output end of the voltage comparator chip N102 outputs high level. When the electrolytic capacitor CX to be detected is reversely connected, the anode of the electrolytic capacitor CX to be detected is connected with the detection end of the first tool testing needle 31, and the cathode of the electrolytic capacitor CX to be detected is connected with the detection end of the second tool testing needle 32. The reversely connected electrolytic capacitor CX to be tested is connected with the resistor R2 in parallel, and the partial voltage on the resistor R2 is still kept at 5V; the voltage of the reverse input end of the corresponding voltage comparator chip N102 is 5V and is less than 5.5V of the voltage of the same-phase input end, and the output end of the voltage comparator chip N102 outputs low level.
The control indicating circuit mainly has the functions of controlling the power-on/power-off condition of partial load and indicating the forward/reverse insertion condition of the capacitor to be measured through the pull-in and release of the relay K1. The control indicating circuit consists of a relay control circuit and an indicating circuit.
The relay control circuit comprises a power supply, a relay K1, a second protective resistor R8, a triode B1 and a protective diode V6. The direct-current power supply, the relay K1, the second protective resistor R8 and the triode B1 are sequentially connected in series; the negative electrode of the protective diode V6 is connected with the connection part between the relay K1 and the power supply, the positive electrode of the protective diode V6 is connected with the connection part between the relay K1 and the triode B1, the two ends of the protective diode V6 are respectively connected with the two ends of the relay K1, and the protective diode V6 is connected with the relay K1 in parallel. When the relay K1 is powered on and attracted, the protection diode V6 is in a cut-off state, when the relay K1 is powered off and released, the protection diode V6 is in a conducting state, and the protection diode V6 is used for preventing electromotive force breakdown in the attraction and release processes of the relay K1. The specific connection mode of the triode B1 is as follows, the collector of the triode B1 is connected with the second protection resistor R8, the emitter of the triode B1 is grounded (the emitter is connected with the ground), the base of the triode B1 is connected with the first end of the first protection resistor R4, and the second end of the first protection resistor R4 is connected with the output end of the voltage comparator chip N102. The first protection resistor R4 is used as a protection resistor to limit current in the circuit, and the voltage of the output end of the voltage comparator chip N102 controls the on-off of the triode B1; when the output end of the voltage comparator chip N102 outputs a high level, the collector electrode and the emitter electrode of the triode B1 are in a conducting state, the relay control circuit is conducted, and the relay K1 is electrified and is in a pull-in state; when the output end of the voltage comparator chip N102 outputs low level, the collector and the emitter of the triode B1 are in a cut-off state, the relay control circuit is not conducted, and the relay K1 is in a release state due to power failure.
The indicating circuit is controlled by a first switch S1 and a second switch S2 regulated by a relay K1. The first switch S1 and the second switch S2 are both normally closed switches; when the relay K1 is released, the first switch S1 and the second switch S2 are closed; when the relay K1 is engaged, the first switch S1 and the second switch S2 are opened. In this embodiment, two ends of the first switch S1 are respectively connected to the terminal of the first tool circuit and the second end of the resistor R2, so as to control the power on or power off of the electrolytic capacitor CX to be tested; when the relay K1 is attracted, the first switch S1 is switched off, and the electrolytic capacitor CX to be detected loses power; when the relay K1 is released, the second switch S2 is closed, and the electrolytic capacitor CX to be tested is electrified. The indicating circuit is controlled by a second switch S2, and a 12V direct-current power supply, a resistor R7, a light-emitting diode indicator lamp (LED indicator lamp) V5 and a ground wire are sequentially connected in series; the cathode of the LED indicator lamp V5 is connected with the ground wire, and the anode is connected with the seventh resistor. When the relay K1 is switched on, the second switch S2 is switched off, the indicating circuit is powered off, and the LED indicating lamp V5 is turned off; when the relay K1 is released, the second switch S2 is closed, the indicating circuit is electrified, and the LED indicating lamp V5 is lightened.
The electrolytic capacitor CX to be detected is not connected, the polarity detection circuit of the electrolytic capacitor is not electrified, and all power supply voltages in the circuit are equal to 0; at this time, the relay K1 loses power and releases, and the first switch S1 and the second switch S2 are both in a closed state. After the electrolytic capacitor CX to be detected is connected, the electrolytic capacitor polarity detection circuit is electrified, and the electrolytic capacitor polarity detection circuit has two states: the electrolytic capacitor CX to be tested is positively connected, and the electrolytic capacitor CX to be tested is reversely connected.
When the electrolytic capacitor CX to be detected is positively connected, the negative electrode of the electrolytic capacitor CX to be detected is connected with the detection end of the first tool testing needle 31, and the positive electrode of the electrolytic capacitor CX to be detected is connected with the detection end of the second tool testing needle 32. The positively connected electrolytic capacitor CX to be tested is connected in parallel with the resistor R2, and under the action of the electrolytic capacitor, the voltage of the second end of the resistor R2 is increased, so that the voltage of the reverse input end of the voltage comparator chip N102 is greater than that of the in-phase input end, and the output end of the voltage comparator chip N102 outputs high level. The output end of the voltage comparator chip N102 outputs high level, so that the collector and the emitter of the triode B1 are in a conducting state, the relay control circuit is conducted, and the relay K1 is electrified and is in a pull-in state. When the relay K1 is in attraction, the first switch S1 and the second switch S2 are both switched off, the electrolytic capacitor CX to be tested loses power, and the indicating circuit power-loss LED indicating lamp V5 is turned off. And powering off the circuit and finishing detection.
When the electrolytic capacitor CX to be detected is reversely connected, the anode of the electrolytic capacitor CX to be detected is connected with the detection end of the first tool testing needle 31, and the cathode of the electrolytic capacitor CX to be detected is connected with the detection end of the second tool testing needle 32. The reversely connected electrolytic capacitor CX to be tested is connected in parallel with the resistor R2, and the voltage of the second end of the resistor R2 is unchanged, so that the voltage of the reverse input end of the voltage comparator chip N102 is smaller than that of the non-reverse input end, and the output end of the voltage comparator chip N102 outputs low level. The output end of the voltage comparator chip N102 outputs low level, so that the collector and the emitter of the triode B1 are in a cut-off state, the relay control circuit is disconnected, and the relay K1 is in a release state due to power failure. When the relay K1 is released, the first switch S1 and the second switch S2 are both closed, the electrolytic capacitor CX to be tested loses power, the indicating circuit is powered, and the LED indicating lamp V5 is lightened. And powering off the circuit and finishing detection.
In conclusion, when the electrolytic capacitors are reversely connected, the LED indicator lamp V5 of the electrolytic capacitor polarity detection circuit is lightened; when the electrolytic capacitor is connected positively, the LED indicator lamp V5 of the electrolytic capacitor polarity detection circuit is turned off.
The invention also provides an electrolytic capacitor polarity detection device, and the specific embodiment is described below with reference to fig. 2 and 3.
The electrolytic capacitor polarity detection device adopts the electrolytic capacitor polarity detection circuit, and is additionally provided with an FCT test frame 51, an FCT test frame power switch 55, a power plug 55 and other components to form a set of FCT test device, and the circuit schematic diagram of the electrolytic capacitor polarity detection device is shown in fig. 2. Compared with the electrolytic capacitor polarity detection circuit, the electrolytic capacitor polarity detection device is provided with a third switch S3 at the control indicating circuit part, and two ends of the third switch S3 are respectively connected with the live wire and the FCT test frame 51; the third switch S3 is controlled by the relay K1 together with the first switch S1 and the second switch S2. When the relay K1 is electrified and attracted, the third switch S3 is closed, and the FCT testing device is electrified to carry out the next testing; when the relay K1 loses power and is released, the third switch S3 is switched off, the FCT testing device loses power, and the detection is finished.
As shown in fig. 3, an FCT test jig power switch 54, a power plug 55, an electrolytic capacitor polarity detection circuit, a first tool test pin 31, a second tool test pin 32, a third tool test pin 56, a fourth tool test pin 57, and a test jig latch 52 are disposed on an FCT test jig 51, thereby forming an FCT test apparatus. The power plug 55 and the power supply of the FCT test frame 51 are arranged on the FCT test frame 51 and provide power supply for the FCT test device; the test frame buckle 52 fixes the circuit board 53 to be tested on the FCT test frame 51, limits the circuit board 53 to be tested, facilitates the test to position the electrolytic capacitor CX to be tested, and connects the electrolytic capacitor into the circuit 3; the first tool testing needle 31 and the second tool testing needle 32 are used for connecting the electrolytic capacitor CX to be tested to an electrolytic capacitor polarity detection circuit and testing whether the electrolytic capacitor is reversely inserted or not; the electrolytic capacitor polarity detection device supplies power to the circuit board through the third tool testing pin 56 and the fourth tool testing pin 57 for the next testing.
The electrolytic capacitor polarity detection device detects the electrolytic capacitor in the circuit board 53 to be detected as follows:
firstly, a power plug 55 is connected with a power supply, the circuit board 53 to be tested is fixed and limited through a test jig buckle 52, the electrolytic capacitor of the circuit board 53 to be tested is ensured to be in good contact with the first tool test needle 31 and the second tool test needle 32, and the power supply port of the circuit board 53 to be tested is ensured to be in good contact with the third tool test needle 56 and the fourth tool test needle 57. Next, the FCT test jig power switch 54 is closed to supply power to the electrolytic capacitor polarity detection device, and the corresponding electrolytic capacitor CX to be detected is connected to the electrolytic capacitor detection circuit through the first tool test pin 31 and the second tool test pin 32 to perform electrolytic capacitor polarity detection.
When the electrolytic capacitor CX to be detected is inserted reversely, the polarity detection circuit of the electrolytic capacitor controls the release of the relay K1; accordingly, the third switch S3 is turned off, the next detection is not performed, the first switch S1 and the second switch S2 are turned on, and the LED indicator V5 is turned on to indicate that the polarity of the electrolytic capacitor is reversed. When the electrolytic capacitor CX to be detected is inserted positively, the polarity detection circuit of the electrolytic capacitor controls the relay K1 to pull in; accordingly, the third switch S3 is closed, the next detection is performed, and the first switch S1 and the second switch S2 are opened, and the LED indicator lamp V5 is turned off.
In conclusion, the electrolytic capacitor polarity detection circuit and the electrolytic capacitor polarity detection device can complete the detection of whether the electrolytic capacitor is reversely inserted, and can indicate through the LED indicator lamp V5 when the electrolytic capacitor is reversely inserted, so that the reliability reduction and the function failure of a circuit board caused by reverse insertion of the polarity are avoided.
The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention in other forms, and any person skilled in the art may apply the above modifications or changes to the equivalent embodiments with equivalent changes, without departing from the technical spirit of the present invention, and any simple modification, equivalent change and change made to the above embodiments according to the technical spirit of the present invention still belong to the protection scope of the technical spirit of the present invention.
Claims (10)
1. An electrolytic capacitor polarity detection circuit, characterized in that: the device comprises a power circuit, a detection circuit, a comparison circuit and a control indication circuit, wherein the detection circuit is used for accessing a capacitor to be detected, the comparison circuit outputs different levels when the capacitor to be detected is inserted positively and reversely, and the control indication circuit is used for controlling the working state of a load in the circuit and indicating;
the power supply circuit comprises a first voltage division circuit, a rectifying circuit and a voltage stabilizing filter circuit; the rectifier circuit is a bridge-type rectifier circuit with four connecting ports, which is formed by annularly connecting four diodes, wherein the port at the connecting position of the anode and the cathode of two diodes is a first output end of the rectifier circuit; the other two diodes are opposite in position, and the port at the connection position of the negative electrode and the negative electrode is a second output end of the rectifying circuit; the other two ports of the bridge type rectifying circuit are respectively a first input end of the rectifying circuit and a second input end of the rectifying circuit;
the detection circuit is coupled with the first voltage division circuit and is connected with the inverting input end of the comparison circuit so as to compare with the preset voltage of the non-inverting input end of the comparison circuit and output a level signal;
the control indicating circuit is connected with the output end of the comparison circuit, and the working state of the control indicating circuit is controlled by the level signal output by the comparison circuit.
2. The electrolytic capacitor polarity detection circuit of claim 1, wherein:
the first voltage division circuit comprises a resistor R1 and a resistor R2, a first end of the resistor R2 is connected with the ground wire, and a second end of the resistor R2 is connected with a first end of the resistor R1;
the two ends of the alternating current stabilized voltage supply are connected with a first input end of a rectifying circuit and a second input end of the rectifying circuit of the bridge type rectifying circuit, a first output end of the rectifying circuit is connected with a first end of a resistor R1, and a second output end of the rectifying circuit is connected with a ground wire;
the voltage stabilizing filter circuit comprises a voltage stabilizing chip N101 and a filter capacitor C1, wherein the input end of the voltage stabilizing chip N101 is connected with the first output end of the rectifier circuit, the grounding end of the voltage stabilizing chip N101 is connected with the ground wire, the output end of the voltage stabilizing chip N101 is connected with the positive electrode of the filter capacitor C1, and the negative electrode of the filter capacitor C1 is connected with the ground wire.
3. The electrolytic capacitor polarity detection circuit of claim 1, wherein: the comparison circuit comprises a second voltage division circuit, a voltage comparator chip N102, a pull-up resistor R3 and a first protection resistor R4;
the second voltage division circuit comprises a resistor R5 and a resistor R6, the first end of the resistor R5 is connected with the first output end of the rectifying circuit, the second end of the resistor R5 is connected with the first end of the resistor R6, and the second end of the resistor R6 is connected with the ground wire;
the power supply end of a voltage comparator chip N102 is connected with a direct-current power supply, the grounding end of the voltage comparator chip N102 is connected with the ground wire, the non-inverting input end of the voltage comparator chip N102 is connected with the second end of a resistor R5, the inverting input end of the voltage comparator chip N102 is connected with a detection circuit, the output end of the voltage comparator chip N102 is connected with the first end of a first protection resistor R4, and the second end of the first protection resistor R4 is connected with a control indication circuit;
the first end of a pull-up resistor R3 is connected with a power supply, and the second end of a pull-up resistor R3 is connected with the output end of the voltage comparator chip N102.
4. The electrolytic capacitor polarity detection circuit of claim 1, wherein: the detection circuit comprises a first tool test needle, a second tool test needle and an electrolytic capacitor CX to be detected; the two ends of the electrolytic capacitor CX to be detected are respectively connected with a first tool test probe detection end and a second tool test probe detection end; the second tool test pin connecting end is connected with the ground wire, and the first tool test pin connecting end is connected with the reverse input end of the voltage comparator chip N102.
5. The electrolytic capacitor polarity detection circuit of claim 1, wherein: the control indicating circuit comprises a relay control circuit and an indicating circuit; the relay control circuit comprises a relay K1 and a triode B1 controlled by a voltage comparator chip N102; the indicating circuit comprises a first switch S1 and a second switch S2 which are electrically connected with the relay K1, and an LED indicator lamp V5 connected with the second switch S2.
6. The electrolytic capacitor polarity detection circuit of claim 5, wherein: the relay control circuit further comprises a power supply and a second protection resistor R8, wherein the first end of the relay K1 is connected with the power supply, the second end of the relay K1 is connected with the first end of the second protection resistor R8, the second end of the second protection resistor R8 is connected with the collector of the triode B1, and the emitter of the triode B1 is connected with the ground wire; the base electrode of the triode B1 is connected with the voltage comparator chip N102 through a first protection resistor R4;
two ends of a first switch S1 are respectively connected with the connecting end of a first tool test needle and the second end of a resistor R2, two ends of a second switch S2 are respectively connected with an LED indicator lamp V5 and a power supply, and the other end of the LED indicator lamp V5 is connected with a ground wire; the first switch S1 and the second switch S2 are arranged: the first switch S1 and the second switch S2 are opened when the relay K1 is pulled in, and the first switch S1 and the second switch S2 are closed when the relay K1 is released.
7. The electrolytic capacitor polarity detection circuit of claim 5, wherein: the relay control circuit further comprises a protection diode V6, the cathode of the protection diode V6 is connected with the first end of the relay K1, and the anode of the protection diode V6 is connected with the second end of the relay K1.
8. An electrolytic capacitor polarity detection device, characterized in that: the electrolytic capacitor polarity detection circuit comprises the electrolytic capacitor polarity detection circuit of any one of claims 1 to 7, and further comprises an FCT test frame, a test frame buckle, an FCT test frame power switch, a power plug, a third tooling test pin and a fourth tooling test pin, wherein the test frame buckle is arranged on the FCT test frame and used for limiting a circuit board to be tested.
9. The electrolytic capacitor polarity sensing device of claim 8, wherein: the first tool testing needle and the second tool testing needle are respectively connected with two ends of an electrolytic capacitor CX to be tested on a circuit board to be tested, and the third tool testing needle and the fourth tool testing needle are connected with a power supply end of the circuit to be tested.
10. The electrolytic capacitor polarity sensing device of claim 8, wherein: the testing device further comprises a third switch S3, wherein the third switch S3 is electrically connected with a relay K1, and two ends of the third switch S3 are respectively connected with the FCT testing frame and the live wire; the third switch S3 is set to close the third switch S3 when the relay K1 pulls in, and to open the third switch S3 when the relay K1 releases.
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| CN110988752B (en) * | 2019-12-27 | 2022-02-08 | 常州同惠电子股份有限公司 | Capacitance polarity testing method for wire tester |
| CN113296030A (en) * | 2021-05-28 | 2021-08-24 | 南通华裕电子有限公司 | Electrolytic capacitor polarity detection circuit and detection device |
| CN113589200B (en) * | 2021-07-30 | 2023-12-01 | 宁波三星医疗电气股份有限公司 | Super capacitor connection fault detection method and system |
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