CN102129004A

CN102129004A - Method for testing open circuit on PCB

Info

Publication number: CN102129004A
Application number: CN2011100253001A
Authority: CN
Inventors: 刘杰
Original assignee: Suzhou Pixcir Microelectronics Co Ltd
Current assignee: Suzhou Pixcir Microelectronics Co Ltd
Priority date: 2011-01-24
Filing date: 2011-01-24
Publication date: 2011-07-20

Abstract

The invention relates to a method for testing an open circuit on a printed circuit board (PCB). A plurality of circuits are arranged on the PCB. The method comprises the following steps of: firstly, hanging a conductor on the PCB; secondly, connecting a test point on a circuit to be tested to a test circuit; and finally, testing the capacitance values of the circuit to be tested when the conductor is hung and when the conductor is grounded respectively so as to judge whether the circuit to be tested is an open circuit or not. In the method for testing the open circuit on the PCB, due to the adoption of capacitance principle, whether the circuit is connected or not can be judged by only testing the capacitance of one of the test points through a probe when any circuit is tested.

Description

The method of test both opens on the pcb board

Technical field

The present invention relates to a kind of method of test both opens, refer in particular to the method for test both opens on pcb board.

Background technology

Printed circuit board (PCB) (PCB) is the carrier of all electronic products, and it installs various integrated circuit, components and parts and connector, and constitutes various electronic units by the multilayer wiring interconnection.In the production and development process of PCB, be very important to its test.This does not still guarantee the important means of product quality, and can save testing expense.Test at pcb board at present has bare board test in earlier stage, and fundamental purpose is to open circuit or open test, belongs to the test in device stage.And the present invention just is primarily aimed at this bare board test in early stage.

Present stage, traditional method of testing was to do a corresponding measurement jig according to pad locations on the pcb board and size, boring of the position of corresponding PCB and dress test probe on tool, and be connected on the test machine, judge whether conducting by the probe between any two test points then.Because probe itself is just more tiny, so whether conducting between test two test points, probe accurately must be aligned on each test point, that is to say and require the Test Engineer must utilize probe accurately to aim at the position of two test points in the circuit to be measured, operation has not only proposed higher requirement to Test Engineer's technology itself like this, and test the time also occupied the plenty of time, reduced testing efficiency.

So how just to seem particularly important for the user provides a kind of simple more method of testing.

Summary of the invention

The actual technical matters to be solved of the present invention be how to provide a kind of improve testing efficiency and measuring accuracy at the method for testing that whether opens circuit on the pcb board.

In order to realize above-mentioned purpose of the present invention, the invention provides a kind of on pcb board the method for test both opens, wherein said pcb board is provided with some circuits, its step is as follows: at first, a unsettled conductor on described pcb board; Secondly, a test point on the circuit to be measured is connected on the test circuit; At last, respectively under the described conductor vacant state and ground state under the test circuit to be measured capacitance, whether open circuit thereby judge circuit to be measured.

Of the present invention on pcb board the method for test both opens owing to only need carry out capacity measurement by the test point that probe is treated the survey line road, thus convenient when the Test Engineer tests, and saved the time, also improved testing efficiency; Moreover whether the present invention utilizes capacitance principle to judge on the pcb board to open circuit, and has also improved the accuracy of judging.

Description of drawings

Fig. 1 is the structural representation of the unsettled conductor in pcb board of the present invention top;

Fig. 2 is an out of circuit test method flow diagram on the pcb board of the present invention.

Embodiment

The present invention is further illustrated below in conjunction with drawings and Examples.

See also shown in Figure 1ly, etching has some circuits on the pcb board 1 of the present invention, and the circuit that is used to provide part on the pcb board connects, and the intersection point place of every circuit is called test point.Pcb board of the present invention top is unsettled a conductor 2, owing to have certain distance between pcb board and the conductor 2, so also can produce certain electric capacity between the two.

End with a test point in the circuit to be measured is connected on the test circuit by probe earlier, and another test point is owing to the influence of unsettled conductor 2, so just can test out the capacitance of test point this moment.After being connected on the test circuit 3 as the test point A on any circuit AB among Fig. 1 by probe, because conductor 2 itself can produce an electric capacity relative to the earth, so just can test out the capacitance between circuit AB on pcb board this moment, we claim conductor 2 to test under vacant state that the capacitance between circuit is first capacitance on the pcb board.And then with unsettled conductor 2 ground connection, measure the capacitance of circuit A B spare this moment, because conductor ground connection 2 this moment, and described pcb board also can produce an electric capacity relative to the earth, therefore, the electric capacity that is equivalent to circuit AB place at this moment and produces during conductor 2 ground connection in parallel, so, electric capacity between circuit AB can become greatly, and we claim that the capacitance of this moment is second capacitance.Second capacitance that will test out then deducts described first capacitance and judges its difference whether in a threshold value, and described threshold value is empirical value, and the Test Engineer can set in advance.So, if above-mentioned difference thinks then that in described threshold value this measurement circuit AB is conducting, if above-mentioned difference not in described threshold value, thinks that then this measurement circuit AB disconnects.

Of the present invention on pcb board the method for test both opens, so owing to utilized capacitance principle in any circuit of test, only need just can judge whether conducting of circuit by the electric capacity of one of them test point of probe test.So not only method is simple, and save tester's time, therefore also improved work efficiency.

Claims

1. the method for a test both opens on pcb board, wherein said pcb board is provided with some circuits, and its step is as follows:

At first, a unsettled conductor on described pcb board;

Secondly, a test point on the circuit to be measured is connected on the test circuit;

At last, respectively under the described conductor vacant state and ground state under the test circuit to be measured capacitance, whether open circuit thereby judge circuit to be measured.

2. the method for claim 1 is characterized in that: behind the capacitance of obtaining under the above-mentioned two condition, whether whether in threshold value, finally judging circuit to be measured has and opens circuit according to its difference.

3. method as claimed in claim 2 is characterized in that: described difference is if in threshold value, then thinks line conduction to be measured, if described difference not in threshold value, is then thought line broken circuit to be measured.

4. as claim 2 or 3 described methods, it is characterized in that: described threshold value is an empirical value, can set in advance.

5. the method for claim 1, it is characterized in that: described test point is positioned at the intersection point place of every circuit.

6. the method shown in claim 1, it is characterized in that: a test point of described circuit to be measured is connected on the described test circuit by probe.