数字毫秒计是力学实验室中的常用仪器。但大多数毫秒计没有测周期的功能,而力学实验中常要进行周期测量,以下电路可以丝毫不改动毫秒计,为毫秒计增设测周期的功能(以上海华师科教仪器厂的HMJ毫秒计为例)。图1中施密特触发器作输入光电信号整 The digital millisecond meter is a commonly used instrument in mechanics labs. However, most milliseconds do not measure the cycle function, and mechanical experiments often need to measure the cycle, the following circuit can be no change millisecond meter, millisecond meter set the test cycle function (Shanghai Science and Technology Instrument Factory HMJ millisecond as an example ). Figure 1 Schmitt trigger input optical signal for the whole