I'm having problems as well.

Just FYI, here are the taskfile registers (mainly VSCs) for a Samsung HDD whose maintenance cyclinders (MC) are being dumped (1X7 = command register):


The previous dump was generated by the 8-bit version of NazYura's IDE Grabber.

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A backup a day keeps DR away.

This does not answer my question. They have made an assumption that without the diode, using a 24 volt supply, that the back EMF will rise to 240 volts. I wanted to know what the actual back EMF would be with a 12 volt coil.

Besides, the current directions in the diagrams are all wrong. In the field of electronics and in the electrical field, current is deemed to flow from negative to positive. It's only in engineering schools they persist with the incorrect notion of conventional flow from positive to negative.

I had to suffer through that when I returned to the uni to study electrical engineering. Having been immersed in electronics theory based on negative to positive flow, I held my nose and did it. I found in most cases I could simply ignore conventional flow and use my old negative to positive flow to work out problems.

Perhaps a word on that might help people confused by diode markings. On some diodes the diode symbol is used to indicate polarity and the arrow points in the direction of conventional current flow, from positive to negative. Any one thinking in terms of negative to positive electron flow must think of current flowing against the arrow. Same with BJT transistors.

Many diodes simply have a bar on one end which indicated the cathode end of the diode.