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在全国企业整顿验收和计量定级、升级的条例中规定,对在用仪器仪表的完好率(合格率)必须达到95％以上。企业要达到此指标,必须对仪器仪表进行检定维修,特别是要合理安排计量检定周期。本文谈谈如何实现的问题。一、电子产品的失效率与可靠度电子产品的可靠度R(t)可近似为: R(t)=e~(-λ(t)t)=e~(-t/θ)(1)式中,λ(t)-失效率,表示产品在某一单位时间内的失效数。电子产品在剔除早期失效后,在相当长的时间内,λ(t)=常数=λ;θ——平均寿命;t-产品两次相邻故障之间的工作时间。下图为据式(1)按产品不同的λ所绘制的不同可靠度曲线。从图中可知,产品的λ越低,或平均寿命θ越长,R(t)越高,则平均无故障工作时间t越长。例如,某通用晶体管示波器平均寿命θ=5000小时,要求可靠度R(t)=0.95的平均无故障间隔的时间可从式(1)解得t=256小时。这就说明,一台合
Regulation and acceptance of the national consolidation and measurement of the level of regulation, the provisions of the regulations, the use of instrumentation in good rate (pass rate) must reach more than 95%. Enterprises to achieve this target, the instrument must be tested and repaired, in particular, to arrange a reasonable measurement test cycle. This article talks about how to achieve the problem. First, the failure rate and reliability of electronic products The reliability of electronic products R (t) can be approximated as: (1) Where, λ (t) - failure rate, said the product in a unit of time the number of failures. Λ (t) = constant = λ; θ - average life span; t - working time between two adjacent faults of the product after the early failure of the electronic product is removed. The following figure shows the different reliability curves according to formula (1) according to different products λ. It can be seen from the figure that the lower the λ of the product or the longer the average life span θ, the higher R (t) is, the longer the mean time between failures t is. For example, a typical transistor oscilloscope with an average life span of θ = 5000 hours requires an average time between failures of R (t) = 0.95 for t = 256 hours from Eq. (1). This shows that a Taiwan