直至最近,信号的程序和开关几乎完全依靠机电式继电器和机械开关进行控制。目前电子开关通称是模拟开关,正用作许多这类用途。最先,电子开关在许多场合代替了继电器,但是很快使模拟开关具备了机械开关从来未有的独特性能。特别是,一只普通电子开关的动作约比平常的继电器要快一千倍。 Until recently, signal procedures and switches were almost entirely controlled by electromechanical relays and mechanical switches. At present, electronic switches, commonly known as analog switches, are being used for many of these applications. First, the electronic switch replaced the relay on many occasions, but soon the analog switch was unique in mechanical switching. In particular, an ordinary electronic switch moves about a thousand times faster than a normal relay.