CN110988752A

CN110988752A - Capacitance polarity testing method for wire tester

Info

Publication number: CN110988752A
Application number: CN201911374323.6A
Authority: CN
Inventors: 刘亚国; 周玉; 王恒斌; 赵浩华; 刘瑜
Original assignee: Changzhou Tonghui Electronics Co ltd
Current assignee: Changzhou Tonghui Electronics Co ltd
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2020-04-10
Anticipated expiration: 2039-12-27
Also published as: CN110988752B

Abstract

The invention relates to a capacitance polarity testing method for a wire tester, which comprises the following steps: applying a constant current to pin 1 and pin 2 of the capacitor, and charging for a plurality of times T1 to increase the voltage of the capacitor to V1; then discharging through a resistor R, and from the beginning of discharging, sampling and integrating the voltage at the two ends of the capacitor, wherein the value of the voltage is S1; then, in turn, a constant current is applied between pin 2 and pin 1 of the capacitor, and the capacitor voltage is increased to V1 after charging for a plurality of times T2; then discharging through a resistor R, and from the beginning of discharging, sampling and integrating the voltage at the two ends of the capacitor, wherein the value of the voltage is S2; finally, comparing S1 with S2, if S1> S2 indicates that 1 pin is positive; if S2> S1 indicates that the 2-pin is positive. The invention does not need to fully charge the capacitor, only needs to charge a little electric quantity, and is easy to discharge the electric quantity in the capacitor in the discharging stage, so the time consumption is little, and the testing time is greatly shortened; and the misjudgment rate is less than 1%.

Description

Capacitance polarity testing method for wire tester

Technical Field

The invention relates to the field of electronic test, in particular to a capacitance polarity test method for a wire tester.

Background

In the prior art, a wire rod with a large capacity of an electrolytic capacitor is arranged in the wire rod, and when the wire rod is tested, the capacity value and the polarity of the capacitor are required to be tested, so that the capacitor is ensured not to be reversely arranged.

The traditional testing method is to distinguish the polarity of the capacitor according to the resistance of the capacitor when the capacitor is fully charged in the forward direction and fully charged in the reverse direction, wherein the larger resistance is the positive electrode, and the specific steps are as follows: firstly, applying a 4V constant voltage between pins 1 and 2 of a capacitor, charging for a plurality of times T1, and then detecting the resistance value R1 of the capacitor; then discharging, and discharging the electricity in the capacitor; then, in turn, a constant voltage of 4V is applied between the pin 2 and the pin 1 of the capacitor, charging is carried out for a plurality of times T1, and then the resistance value R2 of the capacitor is detected; then discharging, and discharging the electricity in the capacitor; finally, comparing R1 with R2, if R1> R2 indicates that 1 pin is positive; if R2> R1 indicates that 2 pins are positive.

However, the charging time T1 is determined according to the capacitance of the measured capacitance, that is, the charging time T1 is longer as the capacitance value of the measured capacitance is larger. If the charging time is not enough, the misjudgment rate is very large, so the charging time must be ensured to be sufficient, and the charging time of several seconds is required for the arrangement of some large capacitors, so the method is very time-consuming and the test efficiency is very low. Moreover, even if the charging time is enough, the misjudgment rate of the method is found to be very high after a plurality of tests and practices.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the capacitance polarity testing method for the wire tester is provided, and the capacitance polarity can be quickly and accurately tested.

The principle of the invention is as follows: in the research process of charging and discharging a capacitor, a phenomenon exists: a capacitor is charged in a positive direction, the voltage of the capacitor is assumed to be V1, the capacitor is discharged through a resistor, and the discharge curve is relatively gentle, namely, the voltage drop is relatively slow, and the discharge time is relatively long; then, through reverse charging, assuming that the voltage is also V1, discharging is carried out through a resistor, and the discharging curve is steeper, namely, the voltage drops faster and the discharging time is shorter; therefore, the invention utilizes the difference of the discharge curves of the two capacitors to distinguish the polarity of the capacitor.

The technical scheme adopted by the invention for solving the technical problems is as follows: a capacitance polarity testing method for a wire tester comprises the following steps:

1) applying a constant current between the pin 1 and the pin 2 of the capacitor to be measured, and charging for a time T1 to enable the voltage of the capacitor to be measured to rise to V1;

2) discharging the capacitor to be measured through a resistor R, and sampling and integrating voltages at two ends of the capacitor to be measured from the beginning of discharging, wherein an integral value is S1;

3) performing reverse action, applying the same constant current as the constant current in the step 1) between the pin 2 and the pin 1 of the capacitor to be measured, and charging for the time T2 to enable the voltage of the capacitor to be measured to rise to V1;

4) discharging through the same resistor R as in the step 2), and sampling and integrating the voltage at two ends of the capacitor to be measured from the beginning of discharging, wherein the integral value is S2;

5) comparing S1 with S2, and if S1 is greater than S2, taking the 1 pin of the capacitor to be detected as the anode; and if S2> S1, the 2 pin of the capacitor to be detected is the positive electrode.

Further, the constant current in the step 1) is 20-25 mA.

Still further, in step 2), the voltage at two ends of the capacitor to be measured is sampled in the following manner: sampling once at intervals of delta T and lasting for a sampling time T_mTo obtain

For each sample data, all the sample data are integrated to obtain S1.

Still further, in step 4), the voltage at two ends of the capacitor to be measured is sampled in the following manner: sampling once at intervals of delta T' and lasting for a sampling time T_m', co-obtain

For each sample data, all the sample data are integrated to obtain S2.

The invention has the advantages that the defects in the background technology are overcome, the capacitor is not required to be fully charged, only a small amount of electricity is required to be charged, and the electricity in the capacitor is easily discharged in the discharging stage, so that the time consumption is little, and the testing time is greatly shortened; in addition, the misjudgment rate of the invention is less than 1%.

Drawings

FIG. 1 is a graph of v-t curves for a capacitor of the present invention discharging after it has been positively charged;

FIG. 2 is a graph of v-t curves for the capacitor of the present invention discharging after reverse charging.

Detailed Description

The invention will now be described in further detail with reference to the drawings and preferred embodiments. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.

A capacitance polarity testing method for a wire tester comprises the following steps:

1) a constant current of 20mA is applied to pin 1 and pin 2 of the capacitor, and the capacitor voltage is increased to V1 after charging for a plurality of time T1.

2) The discharge is performed through a resistor R, and from the beginning of the discharge, the voltage across the capacitor is sampled and integrated, and its value is S1.

3) In the reverse operation, a constant current of 20mA is applied between pin 2 and pin 1 of the capacitor, and the capacitor voltage is increased to V1 after charging for a certain time T2.

4) The discharge is performed through a resistor R, and from the beginning of the discharge, the voltage across the capacitor is sampled and integrated, and its value is S2.

5) Finally, comparing S1 with S2, if S1> S2 indicates that 1 pin is positive; if S2> S1 indicates that the 2-pin is positive.

The method specifically comprises the following steps:

1. applying a constant current of 20mA to pin 1 and pin 2 of the capacitor, continuously and circularly sampling the voltage at two ends of the capacitor, and stopping charging when the voltage reaches 1V.

2. Then switching to a discharge loop, discharging through a 100 ohm resistor, sampling and integrating the voltage at two ends of the capacitor from the beginning of discharging, sampling for 1 time in 0.1ms (delta t), continuously sampling for 20ms, and recording 200 sampling data as: v1, v2, … …, v 200; the discharge curve is shown in fig. 1, the area of S1 in fig. 1 is the sampled integral value,

3. and then, conversely, applying a constant current of 20mA between the pin 2 and the pin 1 of the capacitor, continuously and circularly sampling the voltage at the two ends of the capacitor, and stopping charging when the voltage reaches 1V.

4. Then switching to a discharge loop, discharging through a 100 ohm resistor, sampling and integrating the voltage at two ends of the capacitor from the beginning of discharging, sampling for 1 time in 0.1ms (delta t'), and sampling for 20ms continuously, wherein 200 sampling data are recorded as: v1 ', v2 ', … …, v200 '; as shown in fig. 2, the area of S2 in fig. 2 is the sampled integral value,

5. finally, comparing S1 with S2, if S1> S2 indicates that 1 pin is positive; if S2> S1 indicates that the 2-pin is positive.

The method does not need to fully charge the capacitor, only needs to charge a little electric quantity, and the charging current of 20mA can be charged to 1V voltage within millisecond time, so that the time consumption is little. The discharge phase, sampling 20ms, is also very time consuming. Since the front electric quantity is less charged, the discharging is fast, and the electric quantity in the capacitor is easily discharged. Therefore, the time consumption of the whole testing process is controlled to be 100ms to 500ms, and the testing time is greatly shortened. After long-time tests and practices, the misjudgment rate of the method is less than 1%, and no misjudgment condition is found at present.

While particular embodiments of the present invention have been described in the foregoing specification, various modifications and alterations to the previously described embodiments will become apparent to those skilled in the art from this description without departing from the spirit and scope of the invention.

Claims

1. A capacitance polarity testing method for a wire tester is characterized by comprising the following steps:

2. The capacitance polarity testing method for the wire tester as claimed in claim 1, wherein: the constant current in the step 1) is 20-25 mA.

3. The capacitance polarity testing method for the wire tester as claimed in claim 1, wherein: in the step 2), the voltage at two ends of the capacitor to be tested is sampled in the following mode: sampling once at intervals of delta T and lasting for a sampling time T_mTo obtain

For each sample data, all the sample data are integrated to obtain S1.

4. The capacitance polarity testing method for the wire tester as claimed in claim 1, wherein: in the step 4), the voltage at the two ends of the capacitor to be tested is sampled in the following mode: sampling once at intervals of delta T' and lasting for a sampling time T_m', co-obtain

For each sample data, all the sample data are integrated to obtain S2.