Detail of JJG 237-2010

Introduction of JJG 237-2010

1 Scope This Regulation applies to initial verification, subsequent verification and in-service inspection of stopwatches (electronic stopwatch, mechanical stopwatch, pointer-type electric stopwatch and digital-type electric stopwatch). 2 Normative References JJF 1001-1998 General Terms in Metrology and Their Definitions JJF 1002-1998 The Rules for Drafting National Metrological Verification Regulation JJF 1180-2007 Glossary and Definition of Time and Frequency Metrology GB/T 22773-2008 Mechanical Stopwatch GB/T 22778-2008 Liquid Crystal Digital Quartz Stopwatches While using this Regulation, current valid editions of such documents shall be applied. 3 Terms and Definitions 3.1 day error measuring error of an electronic stopwatch at a time interval of 1 day. 3.2 time base measuring unit time of a digital-type electric stopwatch. 3.3 time offset difference between actual value and nominal value of time base. 3.4 time base accuracy maximum extent of time offset, expressed by the relative value without symbol. 3.5 inherent error error caused by driving mechanism in the pointer-type electric stopwatch. 4 General Stopwatch is a kind of simple measuring instrument that measures time interval, which is classified into electronic stopwatch, mechanical stopwatch and electric stopwatch.

Contents of JJG 237-2010

1 Scope 2 Normative References 3 Terms and Definitions 4 General 5 Metrological Performance Requirements 5.1 Electronic Stopwatches 5.2 Mechanical Stopwatches 5.3 Pointer-type Electric Stopwatches 5.4 Digital-type Electric Stopwatches 6 General Technical Requirements 7 Measuring Instrument Control 7.1 Verification Conditions 7.2 Verification Items and Methods 7.3 Settlement Based on Verification Results 7.4 Verification Period Annex A Verification Certificate (Inside Page Format) Annex B Verification Result Notification (Inside Page Format)