大多数固体定时器的额定电流只有1A,而且额定电压不高于240V_(AC),要寻求一只过零转换的480V_(AC)固体定时器几乎是不可能的。然而,固体继电器SSR具有较高的电流、电压额定值而且容易买到,因此本设计利用通用可编程定时器IC来控制任何型号的固体继电器,使其转变成固体定时器,从而组成延时和工作模 Most solid-state timers have a current rating of only 1A and rated at no more than 240V AC, it is almost impossible to look for a 480V AC solid-state timer with zero-crossing. However, the solid state relay SSR has a high current and voltage rating and is readily available, so the design uses a general-purpose programmable timer IC to control any type of solid-state relay and convert it into a solid-state timer to form the delay and Work mode