将袖珍计算器的■键(有的型号是田号键)的接点引出,用干簧继电器或光导二极管构成通路,则袖珍计算器就能当计数器用。大多数现在通用的低价计算器都有内定常数的特点,也都可使用(见图1)。如果将○(?)输入计算器,以后每按一次(?)键,就将在总和上加1。因而,如果使用外接点,则计算器就计数出接点接通的次数,同时显示器显出此接通次数多记一次的数来。 Pocket calculator keys (some models are Tian key) leads out, with reed relays or photodiodes constitute access, the pocket calculator can be used when the counter. Most commonly used low-cost calculators have built-in constant features and are also available (see Figure 1). If you enter ○ ()) into the calculator, each time you press the? Key once, you add 1 to the sum. Thus, if an external contact is used, the calculator counts the number of contact turns on and the display shows the number of times this contact is made.