A circuit for detecting positive and negative electrodes of electrolytic capacitors

Abstract

The present invention belongs to the technical field of electrolytic capacitor detection, specifically a circuit for detecting the positive and negative poles of an electrolytic capacitor, including: a power supply VCC, an operational amplifier U1A, a reverse connection alarm circuit, and a positive connection indication circuit. The power output end of the power supply VCC is connected to one pole of a switch S1, and the other pole of the switch S1 is connected to the reverse connection alarm circuit and the positive connection indication circuit. The positive power supply pin of the operational amplifier U1A is connected to the power supply VCC, the negative power supply pin of the operational amplifier U1A is grounded, and the + input pin of the operational amplifier U1A is connected to one end of a current limiting resistor R5. The circuit for detecting the positive and negative poles of an electrolytic capacitor provided by this scheme can accurately detect the positive and negative polarity of an electrolytic capacitor, and can also be used as a method for quickly detecting whether an electrolytic capacitor is damaged. It provides an automated inspection function for the production of patch factories or other occasions, improves production efficiency, and improves the accuracy of production.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic capacitor detection, and in particular to a circuit for detecting positive and negative electrodes of an electrolytic capacitor. Background Art

[0002] An electrolytic capacitor is a type of capacitor. The metal foil is the positive electrode (aluminum or tantalum), the oxide film (aluminum oxide or tantalum pentoxide) in close contact with the positive electrode is the dielectric, and the cathode is composed of a conductive material, an electrolyte (the electrolyte can be liquid or solid) and other materials. The electrolytic capacitor gets its name because the electrolyte is the main part of the cathode.

[0003] Since the current of electrolytic capacitors connected to the power supply in the forward direction is very different from the current of electrolytic capacitors connected to the power supply in the reverse direction, and due to the production process characteristics of electrolytic capacitors, there are positive and negative polarities. Once the positive and negative poles of the electrolytic capacitors are inserted in reverse on the PCBA, the PCBA will not work at best, and the PCBA will burn out and the electrolytic capacitor will explode at worst.

[0004] At present, the polarity of electrolytic capacitors is mostly inspected manually or by optical photos. Manual inspection has certain uncertainties, such as missed inspections, wrong inspections, etc. Optical photo inspection has certain spatial limitations and cannot comprehensively inspect the images produced by optics. Summary of the invention

[0005] The purpose of the present invention is to provide a circuit for detecting the positive and negative poles of an electrolytic capacitor to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a circuit for detecting the positive and negative electrodes of an electrolytic capacitor, comprising:

[0007] Power supply VCC, operational amplifier U1A, reverse connection alarm circuit, positive connection indication circuit;

[0008] The power output end of the power supply VCC is connected to one pole of the switch S1, and the other pole of the switch S1 is connected to the reverse connection alarm circuit and the forward connection indication circuit;

[0009] The positive power supply pin of the operational amplifier U1A is connected to the power supply VCC, the negative power supply pin of the operational amplifier U1A is grounded, the + input pin of the operational amplifier U1A is connected to one end of the current limiting resistor R5, the other end of the current limiting resistor R5 is connected to one end of the sampling protection resistor R1, the other end of the sampling protection resistor R1 is grounded, and a balanced feedback unit is connected between the - input pin and the output pin of the operational amplifier U1A;

[0010] The output pin of the operational amplifier U1A is connected to the reverse connection alarm circuit and the forward connection indication circuit.

[0011] Preferably, the balanced feedback unit includes a balancing resistor R6 with one end connected to the -input pin of the operational amplifier U1A and a feedback resistor R7 connected to the output pin of the operational amplifier U1A, the other end of the feedback resistor R7 is connected to the -input pin of the operational amplifier U1A, and the other end of the balancing resistor R6 is grounded.

[0012] Preferably, the positive connection indication circuit includes an NPN transistor Q5, an NPN transistor Q6 and an LED2, the collector of the NPN transistor Q6 is connected to the cathode of the LED2, the anode of the LED2 is connected to one end of a current limiting resistor R20, the base of the NPN transistor Q6 is connected to one end of a current limiting resistor R17 and one end of a transistor pull-down resistor R19, the other end of the transistor pull-down resistor R19 is connected to the emitter of the NPN transistor Q6 and is grounded, and the other end of the current limiting resistor R17 is connected to the current limiting resistor R1 8, the other end of the current limiting resistor R18 and the other end of the current limiting resistor R20 are connected to the other pole of the switch S1, the collector of the NPN transistor Q5 is connected to the current limiting resistors R17 and R18, the base of the NPN transistor Q5 is connected to one end of the current limiting resistor R15 and one end of the transistor pull-down resistor R16, the other end of the current limiting resistor R15 is connected to the output pin of the operational amplifier U1A, and the emitter of the NPN transistor Q5 is connected to the other end of the transistor pull-down resistor R16 and grounded.

[0013] Preferably, the positive connection indication circuit further includes a delay capacitor C3, the current limiting resistor R17, the current limiting resistor R18, and the collector of the NPN transistor Q5 are connected to the positive electrode of the delay capacitor C3, and the negative electrode of the delay capacitor C3 is grounded.

[0014] Preferably, the reverse connection alarm circuit includes an alarm indicator light circuit and an alarm buzzer circuit.

[0015] Preferably, the alarm indicator light circuit includes a PNP transistor Q1, an NPN transistor Q2 and an LED1, the emitter of the PNP transistor Q1 is connected to the other pole of the switch S1 and one end of the transistor pull-up resistor R4, the other end of one end of the transistor pull-up resistor R4 is connected to the base of the PNP transistor Q1 and one end of the current limiting resistor R3, the collector of the PNP transistor Q1 is connected to the positive pole of LED1, the negative pole of LED1 is connected to one end of the current limiting resistor R2, the other end of the current limiting resistor R2 is grounded, the other end of the current limiting resistor R3 is connected to the collector of the NPN transistor Q2, the emitter of the NPN transistor Q2 is connected to one end of the transistor pull-down resistor R9, the base of the NPN transistor Q2 is connected to the other end of the transistor pull-down resistor R9 and one end of the current limiting resistor R8, and the other end of the current limiting resistor R8 is connected to the output pin of the operational amplifier U1A.

[0016] Preferably, the LED1 is a red indicator light, and the LED2 is a green indicator light.

[0017] Preferably, the alarm indicator light circuit further includes a delay capacitor C2, the positive electrode of the delay capacitor C2 is connected to the base of the NPN transistor Q2, and the negative electrode of the delay capacitor C2 is connected to the emitter of the NPN transistor Q2.

[0018] Preferably, the alarm buzzer circuit includes a PNP transistor Q3, an NPN transistor Q4 and a buzzer LS1, the emitter of the PNP transistor Q3 is connected to one end of the transistor pull-up resistor R11 and the other end of the switch S1, the base of the PNP transistor Q3 is connected to the other end of the transistor pull-up resistor R11 and one end of the current limiting resistor R12, the collector of the PNP transistor Q3 is connected to one end of the current limiting resistor R10, and the other end of the current limiting resistor R10 is connected to the collector of the PNP transistor Q3. One end is connected to one end of the buzzer LS1, the other end of the buzzer LS1 is grounded, the other end of the current limiting resistor R12 is connected to the collector of the NPN transistor Q4, the base of the NPN transistor Q4 is connected to one end of the transistor pull-down resistor R13 and one end of the current limiting resistor R14, the other end of the current limiting resistor R14 is connected to the output pin of the operational amplifier U1A, and the other end of the transistor pull-down resistor R13 is connected to the emitter of the NPN transistor Q4.

[0019] Preferably, the alarm buzzer circuit further includes a delay capacitor C1, the positive electrode of the delay capacitor C1 is connected to the base of the NPN transistor Q4, and the negative electrode of the delay capacitor C1 is connected to the emitter of the NPN transistor Q4.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The circuit for detecting the positive and negative poles of the electrolytic capacitor provided in this solution can accurately detect the positive and negative polarity of the electrolytic capacitor, and can also be used as a method to quickly detect whether the electrolytic capacitor is damaged. It provides an automated inspection function for production in patch factories or other occasions, thereby improving production efficiency and production accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a circuit schematic diagram of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] Embodiment 1:

[0026] See also Figure 1 ,The present invention provides a technical solution: a circuit for detecting the positive and negative poles of an electrolytic capacitor, comprising: a power supply VCC, an operational amplifier U1A, a reverse connection alarm circuit, and a positive connection indication circuit;

[0027] Among them, the power output end of the power supply VCC is connected to one pole of the switch S1, the other pole of the switch S1 is connected to the reverse alarm circuit and the positive indication circuit, the positive power pin of the operational amplifier U1A is connected to the power supply VCC, the negative power pin of the operational amplifier U1A is grounded, the + input pin of the operational amplifier U1A is connected to one end of the current limiting resistor R5, the other end of the current limiting resistor R5 is connected to one end of the sampling protection resistor R1, the other end of the sampling protection resistor R1 is grounded, a balanced feedback unit is connected between the - input pin and the output pin of the operational amplifier U1A, and the output pin of the operational amplifier U1A is connected to the reverse alarm circuit and the positive indication circuit.

[0028] Analysis of the above content: Use switch S1 to simulate the power switch, and use current source I1 (at the current limiting resistor R5 in the figure) to simulate the current after the electrolytic capacitor is connected to the circuit:

[0029] When the electrolytic capacitor is connected to the power supply VCC in the forward direction, the voltage signal collected by the operational amplifier U1A after the switch S1 is turned on drives the forward connection indication circuit to work, indicating and reminding the inspection personnel that the electrolytic capacitor is connected to the power supply in the forward direction; the voltage signal collected by the operational amplifier U1A cannot drive the reverse connection alarm circuit.

[0030] When the electrolytic capacitor is connected to the power supply in reverse, after the power switch S1 is turned on, the voltage signal collected by the operational amplifier U1A cannot drive the positive connection indication circuit; the voltage signal collected by the operational amplifier U1A drives the reverse connection alarm circuit, and an alarm is issued based on the reverse connection alarm circuit.

[0031] Embodiment 2:

[0032] See also Figure 1 The present invention provides a technical solution: the balanced feedback unit includes a balancing resistor R6 with one end connected to the -input pin of the operational amplifier U1A and a feedback resistor R7 connected to the output pin of the operational amplifier U1A, the other end of the feedback resistor R7 is connected to the -input pin of the operational amplifier U1A, and the other end of the balancing resistor R6 is grounded.

[0033] Analysis of the above content: Balancing resistor R6 and feedback resistor R7 are used in operational amplifier U1A.

[0034] Embodiment three:

[0035] See also Figure 1 The present invention provides a technical solution: the positive connection indication circuit comprises an NPN transistor Q5, an NPN transistor Q6 and an LED2, the collector of the NPN transistor Q6 is connected to the cathode of the LED2, the anode of the LED2 is connected to one end of a current limiting resistor R20, the base of the NPN transistor Q6 is connected to one end of a current limiting resistor R17 and one end of a transistor pull-down resistor R19, the other end of the transistor pull-down resistor R19 is connected to the emitter of the NPN transistor Q6 and is grounded, the other end of the current limiting resistor R17 is connected to the emitter of the NPN transistor Q6 and is grounded, One end of the current limiting resistor R18 is connected, the other end of the current limiting resistor R18 and the other end of the current limiting resistor R20 are connected to the other pole of the switch S1, the collector of the NPN transistor Q5 is connected to the current limiting resistor R17 and the current limiting resistor R18, the base of the NPN transistor Q5 is connected to one end of the current limiting resistor R15 and one end of the transistor pull-down resistor R16, the other end of the current limiting resistor R15 is connected to the output pin of the operational amplifier U1A, and the emitter of the NPN transistor Q5 is connected to the other end of the transistor pull-down resistor R16 and grounded.

[0036] The reverse connection alarm circuit comprises an alarm indicator light circuit and an alarm buzzer circuit.

[0037] The alarm indicator light circuit includes a PNP transistor Q1, an NPN transistor Q2 and an LED1, the emitter of the PNP transistor Q1 is connected to the other pole of the switch S1 and one end of the transistor pull-up resistor R4, the other end of one end of the transistor pull-up resistor R4 is connected to the base of the PNP transistor Q1 and one end of the current limiting resistor R3, the collector of the PNP transistor Q1 is connected to the positive pole of LED1, the negative pole of LED1 is connected to one end of the current limiting resistor R2, the other end of the current limiting resistor R2 is grounded, the other end of the current limiting resistor R3 is connected to the collector of the NPN transistor Q2, the emitter of the NPN transistor Q2 is connected to one end of the transistor pull-down resistor R9, the base of the NPN transistor Q2 is connected to the other end of the transistor pull-down resistor R9 and one end of the current limiting resistor R8, and the other end of the current limiting resistor R8 is connected to the output pin of the operational amplifier U1A.

[0038] The alarm buzzer circuit includes a PNP transistor Q3, an NPN transistor Q4 and a buzzer LS1, the emitter of the PNP transistor Q3 is connected to one end of a transistor pull-up resistor R11 and the other end of a switch S1, the base of the PNP transistor Q3 is connected to the other end of the transistor pull-up resistor R11 and one end of a current limiting resistor R12, the collector of the PNP transistor Q3 is connected to one end of a current limiting resistor R10, the other end of the current limiting resistor R10 is connected to one end of a buzzer LS1, the other end of the buzzer LS1 is grounded, the other end of the current limiting resistor R12 is connected to the collector of the NPN transistor Q4, the base of the NPN transistor Q4 is connected to one end of a transistor pull-down resistor R13 and one end of a current limiting resistor R14, the other end of the current limiting resistor R14 is connected to the output pin of an operational amplifier U1A, and the other end of the transistor pull-down resistor R13 is connected to the emitter of the NPN transistor Q4. The LED1 is a red indicator light, and the LED2 is a green indicator light.

[0039] Analysis of the above content: When the electrolytic capacitor is forwardly connected to the power supply VCC, after the power switch S1 is turned on, the voltage signal collected by the operational amplifier U1A drives the NPN transistor Q6 to turn on, and the green indicator light LED2 is on; the voltage signal collected by the operational amplifier U1A cannot drive the PNP transistor Q1, NPN transistor Q2, PNP transistor Q3, and NPN transistor Q4 to turn on, the red indicator light LED1 is not on, and the buzzer LS1 does not make a sound.

[0040] When the electrolytic capacitor is reversely connected to the power supply VCC, after the power switch S1 is turned on, the voltage signal collected by the operational amplifier U1A cannot drive the NPN transistor Q6 to turn on, and the green indicator light LED2 is not on; the voltage signal collected by the operational amplifier U1A drives the PNP transistor Q1, NPN transistor Q2, PNP transistor Q3, and NPN transistor Q4 to turn on, the red indicator light LED1 is on, and the buzzer LS1 sounds, giving an alarm sound prompt.

[0041] Embodiment 4:

[0042] See also Figure 1 The present invention provides a technical solution: the positive connection indication circuit also includes a delay capacitor C3, the current limiting resistor R17, the current limiting resistor R18, and the collector of the NPN transistor Q5 are connected to the positive electrode of the delay capacitor C3, and the negative electrode of the delay capacitor C3 is grounded.

[0043] The alarm indicator light circuit further includes a delay capacitor C2, the positive electrode of the delay capacitor C2 is connected to the base of the NPN transistor Q2, and the negative electrode of the delay capacitor C2 is connected to the emitter of the NPN transistor Q2.

[0044] The alarm buzzer circuit further includes a delay capacitor C1, a positive electrode of the delay capacitor C1 is connected to the base of the NPN transistor Q4, and a negative electrode of the delay capacitor C1 is connected to the emitter of the NPN transistor Q4.

[0045] Analysis of the above content: According to the characteristics of electrolytic capacitors, the voltage at both ends cannot change suddenly, and it is a short-circuit phenomenon at the moment the circuit is connected. By connecting delay capacitors C1, C2, and C3 in the circuit, the conduction time of the transistor can be effectively delayed to avoid the occurrence of incorrect detection.

[0046] The sampling protection resistor R1 in this circuit not only acts as a sampling resistor but also plays a role of current limiting, which reduces the charging current of the electrolytic capacitor when it is connected to the circuit, thereby protecting the electrolytic capacitor.

[0047] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A circuit for detecting the positive and negative poles of an electrolytic capacitor, characterized in that: include: Power supply VCC, operational amplifier U1A, reverse connection alarm circuit, forward connection indication circuit, current source I1; Use current source I1 to simulate the current after the capacitor to be tested is connected to the power supply VCC in the forward or reverse direction. The power output end of the power supply VCC is connected to one pole of the switch S1, and the other pole of the switch S1 is connected to the reverse connection alarm circuit and the forward connection indication circuit respectively; The positive power supply pin of the operational amplifier U1A is connected to the power supply VCC, the negative power supply pin of the operational amplifier U1A is grounded, the + input pin of the operational amplifier U1A is connected to one end of the current limiting resistor R5, the other end of the current limiting resistor R5 is connected to one end of the sampling protection resistor R1, the other end of the sampling protection resistor R1 is grounded, a balanced feedback unit is connected between the - input pin and the output pin of the operational amplifier U1A, the balanced feedback unit includes a balanced resistor R6 with one end connected to the - input pin of the operational amplifier U1A and a feedback resistor R7 connected to the output pin of the operational amplifier U1A, the other end of the feedback resistor R7 is connected to the - input pin of the operational amplifier U1A, and the other end of the balanced resistor R6 is grounded; The output pins of the operational amplifier U1A are connected to the reverse connection alarm circuit and the forward connection indication circuit respectively.

2. A circuit for detecting the positive and negative poles of an electrolytic capacitor according to claim 1, characterized in that: The positive connection indication circuit includes an NPN transistor Q5, an NPN transistor Q6 and an LED2, the collector of the NPN transistor Q6 is connected to the negative electrode of the LED2, the positive electrode of the LED2 is connected to one end of the current limiting resistor R20, the base of the NPN transistor Q6 is connected to one end of the current limiting resistor R17 and one end of the transistor pull-down resistor R19, the other end of the transistor pull-down resistor R19 is connected to the emitter of the NPN transistor Q6 and is grounded, and the other end of the current limiting resistor R17 is connected to one end of the current limiting resistor R18. The other end of the current limiting resistor R18 and the other end of the current limiting resistor R20 are connected to the other electrode of the switch S1, the collector of the NPN transistor Q5 is connected to the other end of the current limiting resistor R17 and one end of the current limiting resistor R18, the base of the NPN transistor Q5 is connected to one end of the current limiting resistor R15 and one end of the transistor pull-down resistor R16, the other end of the current limiting resistor R15 is connected to the output pin of the operational amplifier U1A, and the emitter of the NPN transistor Q5 is connected to the other end of the transistor pull-down resistor R16 and grounded.

3. A circuit for detecting the positive and negative electrodes of an electrolytic capacitor according to claim 2, characterized in that: The positive connection indication circuit also includes a delay capacitor C3, the other end of the current limiting resistor R17, one end of the current limiting resistor R18, and the collector of the NPN transistor Q5 are connected to the positive electrode of the delay capacitor C3, and the negative electrode of the delay capacitor C3 is grounded.

4. A circuit for detecting the positive and negative electrodes of an electrolytic capacitor according to claim 2 or 3, characterized in that: The reverse connection alarm circuit comprises an alarm indicator light circuit and an alarm buzzer circuit.

5. A circuit for detecting the positive and negative electrodes of an electrolytic capacitor according to claim 4, characterized in that: The alarm indicator light circuit includes a PNP transistor Q1, an NPN transistor Q2 and an LED1. The emitter of the PNP transistor Q1 is connected to the other pole of the switch S1 and one end of the transistor pull-up resistor R4. The other end of the transistor pull-up resistor R4 is connected to the base of the PNP transistor Q1 and one end of the current limiting resistor R3. The collector of the PNP transistor Q1 is connected to the positive pole of LED1. The negative pole of LED1 is connected to one end of the current limiting resistor R2. The other end of the current limiting resistor R2 is grounded. The other end of the current limiting resistor R3 is connected to the collector of the NPN transistor Q2. The emitter of the NPN transistor Q2 is connected to one end of the transistor pull-down resistor R9 and is grounded. The base of the NPN transistor Q2 is connected to the other end of the transistor pull-down resistor R9 and one end of the current limiting resistor R8. The other end of the current limiting resistor R8 is connected to the output pin of the operational amplifier U1A.

6. A circuit for detecting the positive and negative electrodes of an electrolytic capacitor according to claim 5, characterized in that: The LED1 is a red indicator light, and the LED2 is a green indicator light.

7. A circuit for detecting the positive and negative electrodes of an electrolytic capacitor according to claim 5, characterized in that: The alarm indicator light circuit further includes a delay capacitor C2, the positive electrode of the delay capacitor C2 is connected to the base of the NPN transistor Q2, and the negative electrode of the delay capacitor C2 is connected to the emitter of the NPN transistor Q2.

8. A circuit for detecting the positive and negative electrodes of an electrolytic capacitor according to claim 4, characterized in that: The alarm buzzer circuit includes a PNP transistor Q3, an NPN transistor Q4 and a buzzer LS1, the emitter of the PNP transistor Q3 is connected to one end of a transistor pull-up resistor R11 and the other end of a switch S1, the base of the PNP transistor Q3 is connected to the other end of the transistor pull-up resistor R11 and one end of a current limiting resistor R12, the collector of the PNP transistor Q3 is connected to one end of a current limiting resistor R10, and the other end of the current limiting resistor R10 is connected to the buzzer LS1. The circuit is connected to one end of the buzzer LS1, the other end of the buzzer LS1 is grounded, the other end of the current limiting resistor R12 is connected to the collector of the NPN transistor Q4, the base of the NPN transistor Q4 is connected to one end of the transistor pull-down resistor R13 and one end of the current limiting resistor R14, the other end of the current limiting resistor R14 is connected to the output pin of the operational amplifier U1A, and the other end of the transistor pull-down resistor R13 is connected to the emitter of the NPN transistor Q4 and grounded.

9. A circuit for detecting the positive and negative poles of an electrolytic capacitor according to claim 8, characterized in that: The alarm buzzer circuit further includes a delay capacitor C1, a positive electrode of the delay capacitor C1 is connected to the base of the NPN transistor Q4, and a negative electrode of the delay capacitor C1 is connected to the emitter of the NPN transistor Q4.

Images