很多计算机使用SCSI来连接计算机及其外设.正确的操作要求18条信号线(通常是外部信号线)应正确“端接”.图1a表示计算机信号源.端接点必须能够通过大约120Ω对18条信号线的每一条提供10mA电流(图1b).端接点也必须能吸收电流,视源电压超过端接电压多少而定.一般提供一个需要36个电阻器的无源端接器(图2a).这种类型的端接器从“termpwr”总线消耗大约140mA剩 Many computers use SCSI to connect their computers and their peripherals.The correct operation requires that 18 signal lines (usually external signal lines) be correctly “terminated.” Figure 1a shows the computer’s signal source.The termination point must be capable of passing through approximately 120Ω to 18 Each of the signal lines provides 10mA (Figure 1b). The termination point must also sink current, depending on how much the source voltage exceeds the termination voltage. A 36-Ω passive termination is typically provided (Figure 2a This type of terminator consumes about 140mA left from the “termpwr” bus