图7.9时间继电器的图形符号(a)一般线圈;(b)通电延时线圈;(c)断电延时线圈;(d)通电延时闭合动合(常开)触点; (e)通电延时断开动断(常闭)触点;(f)断电延时断开动合(常开)触点; (g)断电延时闭合动断(常闭)触点;(h)瞬动触点