Method for detecting capacitor deficiency

Abstract

A method for detecting a capacitor loss is applicable to detecting a plurality of by-pass capacitors connected in parallel to each other. The detection method includes the following steps, an alternating current (AC) signal is input into the by-pass capacitors, in which the AC signal has a plurality of test frequencies; test voltages of the by-pass capacitors at each of the test frequencies are recorded, so as to form a test result table; it is determined whether the test result table is the same as a standard voltage table; and when a result of the determination is NO, a fail signal is output. By applying the detection method, whether a loss exists in the by-pass capacitors can be effectively identified, thereby solving the problem that small capacitors are undetectable when large capacitors are connected in parallel to the small capacitors.

Description

technical field [0001] The invention relates to a method for detecting the lack of capacitance, in particular to a detection method for detecting whether a plurality of bypass capacitors connected in parallel are missing. Background technique [0002] Generally speaking, a printed circuit board (PCB) must complete its electrical testing, appearance and surface defect inspection before leaving the factory. Among them, in order to judge the quality of the electrical properties of the circuit board, the electrical testing item is one of the links that the industry attaches great importance to at present. [0003] For example, when an in-circuit tester performs electrical testing on a circuit substrate, its testing items include testing of discrete components such as resistors, inductors, and capacitors. Among them, when detecting capacitance, since most of the circuit substrates have more than one capacitance; that is to say, when the equivalent capacitance is formed by parall...

AI Technical Summary

Problems solved by technology

Therefore, when using the prior art phase difference method, voltage difference method, or capacitance bridge method to measure the total capacitive reactance of the equivalent capacitor, it is impossible to accurately identify whether the small capacitor exists or whether it is missing.

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