Research on the design and application of test circuits for a digital voltmeter

摘要

By providing a typical A/D circuit based on ICL7135 4-1/2 digit voltmeter, the paper focuses on the design of fault test circuit. The principle of digital voltmeter circuit and the main circuit failure modes and mechanisms with FMMEA will be presented, additional new test circuit designs will be demonstrated in the original A/D circuit and the feasibility will be analyzed and clarified. Finally, recommendations and some methods to design test circuit for a few main failure modes will be proposed.