CN110764017A

CN110764017A - Detection method for quickly determining short circuit of electronic device of parallel circuit

Info

Publication number: CN110764017A
Application number: CN201910958398.2A
Authority: CN
Inventors: 马建敏
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2019-10-10
Filing date: 2019-10-10
Publication date: 2020-02-07
Anticipated expiration: 2039-10-10
Also published as: CN110764017B

Abstract

The invention belongs to the technical field of electronics, and particularly relates to a detection method for quickly determining short circuit of an electronic device of a parallel circuit. The impedance of the parallel circuit is measured by using the impedance level of the LCR digital bridge, and the minimum point of the impedance is the position of the short-circuit device in the circuit; the parallel circuit is a circuit formed by connecting a plurality of pure resistors, a plurality of pure capacitors or a plurality of pure inductors in parallel, or a circuit formed by connecting resistors, capacitors and inductors in parallel in a mixed manner, or other parallel circuits which can judge whether the device is short-circuited or not through the impedance. The invention has fast detection speed and is not limited by the number and the type of the parallel devices.

Description

Detection method for quickly determining short circuit of electronic device of parallel circuit

Technical Field

The invention belongs to the technical field of electronics, and particularly relates to a method for detecting short circuit of an electronic device.

Background

In various electronic circuits, different numbers and types of electronic components are connected in parallel for use, and particularly for some circuits using parallel devices in large scale, such as parallel connection of a large number of transducers used in electromagnetic wave or sound wave transmission or reception, parallel connection of LED lamps, and the like, sometimes thousands of devices of the same type or different types are used in parallel. Because of improper welding installation or in the use process, damage to one or more parallel devices is inevitably caused, a circuit is short-circuited, and the whole equipment or system cannot work normally.

In a parallel resistance circuit, if there is a short circuit in the resistance, the position of the short circuit resistance cannot be determined with a multimeter. For a circuit with an inductor or a capacitor connected in parallel or a circuit with a resistor, a capacitor and an inductor connected in parallel in a mixed mode, the multimeter cannot be used, and the inductor is short-circuited when measured by the multimeter. Other measuring methods need special instruments and are complicated in detection process, time consumption for determining the position of the short-circuit device is long, and efficiency for determining the short-circuit position of the large-scale parallel device is low.

Disclosure of Invention

Aiming at the defects in the detection technology, the invention aims to provide a detection method for quickly determining the short circuit of the electronic device of the parallel circuit.

The invention provides a detection method for quickly determining the short circuit of an electronic device of a parallel circuit, which adopts an impedance measurement gear of an LCR digital bridge meeting certain accuracy and frequency requirements to detect and confirm the short circuit device of the tested parallel electronic device, wherein the minimum point of the impedance is the position of the short circuit device in the circuit. The invention can be used for a circuit with a plurality of pure resistors, a plurality of pure capacitors or a plurality of pure inductors connected in parallel, and is shown in figures 2,3 and 4; but also can be used for a circuit with mixed parallel connection of a resistor, a capacitor and an inductor, see figure 1; it can also be used in other parallel circuits that can determine whether the device is short-circuited or not through the impedance. The invention has fast detection speed and is not limited by the number and types of parallel and short-circuit devices.

In the invention, the LCR digital bridge is a conventional instrument used in the field of electronics, but the bridge needs to have an impedance Z measuring gear, and the LCR digital bridge and a parallel circuit with a short-circuit device form a detection system; the impedance Z measurement range should be within Ω -99.99M Ω, the accuracy should reach 0.1%, and the measurement frequency should be continuous or have fixed frequency point within 1 KHz. For short circuit detection of some parallel devices operating in a certain fixed frequency or frequency domain, the measurement frequency range of the used LCR digital bridge should be satisfied.

In the invention, a circuit formed by mixing and connecting resistors, capacitors and inductors in parallel is used, referring to fig. 1, a circuit formed by connecting a plurality of pure resistors in parallel is used, referring to fig. 2, a circuit formed by connecting a plurality of pure capacitors in parallel is used, referring to fig. 3, a circuit formed by connecting a plurality of pure inductors in parallel is used, referring to fig. 4, a test end of the LCR digital bridge is respectively connected with A, B ends (two test points) in fig. 1, fig. 2, fig. 3 and fig. 4, and a C, D end(two test points) are connected, and the impedance Z at the two ends is obtained through testing_ABAnd Z_CDIf Z is_AB<Z_CDIf the A, B end is close to the short-circuit device, the test point is moved rapidly or in a crossing manner from A, B end, the point with the minimum impedance is found according to the trend of the decrease of the impedance, and the position of the short-circuit device is located between the two test points. If Z is_AB>Z_CDThen, starting from the end C, D, the location of the shorting device is found in the same manner as described above.

In the invention, for other parallel circuits which can judge whether the device is short-circuited or not through the impedance, the position of the short-circuited device can be determined by using the detection method.

In the present invention, for the detection of short circuit of some parallel devices operating in a certain fixed frequency (for example, parallel connection of ultrasonic transducers) or frequency domain, the position of the short circuit device can also be determined by the above method, and the measuring frequency of the used LCR digital bridge is consistent with the operating frequency of the device.

The detection method for quickly determining the short circuit of the parallel electronic device is not only suitable for all parallel circuits which judge whether the device is short-circuited or not through the impedance, but also has no specific requirements on the form and the impedance of the device in the detected parallel short circuit, and the detection process can not cause secondary damage to the original circuit.

Drawings

FIG. 1 is a diagram of a resistor, capacitor and inductor hybrid parallel circuit according to the present invention.

Fig. 2 is a schematic representation of a pure resistor parallel circuit of the present invention.

Fig. 3 is a schematic diagram of a pure capacitor parallel circuit according to the present invention.

Fig. 4 is a schematic representation of a pure inductor parallel circuit of the present invention.

Detailed Description

Referring to fig. 1, for a circuit in which resistors, capacitors and inductors are mixed and connected in parallel, if one or more devices are short-circuited, the specific detection and determination method is as follows:

firstly, an LCR digital bridge is selected, parameters are set in an impedance Z measurement gear, and the frequency is selected to be 1 KHz.

Secondly, two measuring pens of an LCR digital bridge are respectively connected with A, B terminals and C, D terminals of FIG. 1, and the impedance Z at the two terminals is tested_ABAnd Z_CDThe specific value can be read from the display screen of the LCR digital bridge. If Z is_AB<Z_CDAnd if the end A and the end B are close to the short-circuit device, the measuring points are quickly or in a spanning mode moved from the end A and the end B, the point with the minimum impedance is found according to the trend of impedance reduction, and the position between the two measuring points is the position of the short-circuit device. If Z is_AB>Z_CDThen, starting from the terminals C and D, the position of the short-circuit device is found by the same method as above. If a plurality of devices are short-circuited, the devices are checked one by the method.

For the circuits of the invention shown in fig. 2, fig. 3 and fig. 4, which are purely connected in parallel, and the parallel circuit which can judge whether the device is short-circuited or not through the impedance, the position of the short-circuited device can be determined by the method.

For devices with a defined frequency operation, such as an ultrasound emitting array consisting of n 40KHz ultrasound transducers connected in parallel, the detection can also be performed in the above-described manner if there are short-circuited transducers, but the frequency of the LCR digital bridge is chosen to be 40 KHz.

Claims

1. A detection method for quickly determining the short circuit of an electronic device in a parallel circuit is characterized in that an LCR digital bridge impedance level is used for measuring the impedance of the parallel circuit, and the minimum point of the impedance is the position of the short circuit device in the circuit; the parallel circuit is a circuit formed by connecting a plurality of pure resistors, a plurality of pure capacitors or a plurality of pure inductors in parallel, or a circuit formed by connecting resistors, capacitors and inductors in parallel in a mixed manner, or other parallel circuits which can judge whether the device is short-circuited or not through the impedance.

2. The detection method capable of quickly determining the short circuit of the parallel electronic devices according to claim 1, wherein the LCR digital bridge and the parallel circuit with the short circuit device form a detection system, the impedance level measurement range of the LCR digital bridge is from 0.0001 Ω -99.99M Ω, the accuracy reaches 0.1%, and the measurement frequency is continuous or has a fixed frequency point within 1 KHz.

3. The detection method for quickly determining the short circuit of the parallel electronic devices as claimed in claim 1, wherein for the parallel circuits with mixed resistors, capacitors and inductors, or for the parallel circuits with multiple pure resistors, multiple pure capacitors or multiple pure inductors, the test terminals of the LCR digital bridge are connected to the test point A, B terminal and the test point C, D terminal of the circuit to be tested, respectively, and the impedance Z at the two terminals is measured_ABAnd Z_CD(ii) a If Z is_AB<Z_CDIf the A, B end is close to the short-circuit device, the measuring point is moved rapidly or in a crossing manner from the A, B end, the point with the minimum impedance is found according to the trend of the reduction of the impedance, and the position of the short-circuit device is between the two measuring points; if Z is_AB>Z_CDThen, starting from the end C, D, the location of the shorting device is found in the same manner as described above.