When the disk drive indicator of a computer cannot be read (since the computer is under or beside the table) it may be useful. If difficulties arise, to have an extended indicator alongside the monitor.
The circuit described here is just that. It consists of a p- n-p transistor, an LED, and two resistors and np-n transistor, an LED and two resistors. Which is to be used depends on The LED drive of the floppy or hard Disk.
The PC drive LED in the computer must be branched off to a D connector to be fitted at the rear of the computer. The small circuit is easily constructed on a small piece of prototyping board and built into a small case. The whole is then connected via a cable terminated to a D connector to the computer. The small case can then be located wherever desired.