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转速是电唱盘的主要技术指标之一。按照国家标准(GB 2354—80)的要求,电唱盘转速的测试方法有两种:第一种是秒表计数法,即用秒表对唱盘转动100周进行计时,然后再进行计算。第二种为频闪测速法,即用频闪测速片和频闪光源(氖灯或日光灯)进行。上述的两种方法都有一定的缺陷;前者测量时间太长,不适宜生产厂大批量生产检测,后者虽然测量速度较快,但不易读出转速的实际值,而且它要求频闪光源使用的电源频率为恒定的50Hz,如果直接使用市电,一旦市电频率变化就会给观测带来较大的误差。为了解决上述问题,这里介绍几种电唱盘转速测量的数字显示装置,供有关人员参考。
Speed is one of the main technical indicators of turntables. According to the national standard (GB 2354-80) requirements, there are two ways to test the speed of the turntable: The first is the stopwatch counting method, which uses the stopwatch to count the turntable for 100 weeks and then calculate. The second is stroboscopic tachymetry, which uses flash stroboscopes and stroboscopic light sources (neon or fluorescent). The above two methods have certain defects; the former measurement time is too long, not suitable for mass production testing factory, the latter although the measurement speed, but not easy to read out the actual value of speed, and it requires the use of strobe light Of the power frequency is constant 50Hz, if the direct use of electricity, once the change in mains frequency will give the observation a greater error. In order to solve the above problems, here are several digital display dial speed measurement for reference.