I do get what you're saying.
Maybe I didn't know the terminology to explain it best, but the idea of my first circuit was on that concept.
Lets recap:
**broken link removed**
On the left of the red line we have the outputs of the ecu, one fixed 12v feed and a switched earth. Obviously proteus doesn't have an 'ecu module' so I simulated it with a permanent live and an earth. With a switch.
It's basic but at an electrical level it's the same thing, i just have to flick the switch really fast
Inbetween the red and blue we have my mosfet, with that resistor. Now in the original circuit, thats where my solenoid would be. Instead we have a resistor in it's place which pulls the gate high when the earth is disconnected.
We also have the mosfet conencted to the 12v supply at the top, so that when the gate goes high, current flows.
So you see, in concept it works. When earth switch is off (open), gate is on.
Audioguru actually came within a millimeter of solving my problem whilst he was calling me thick, because he mentioned swapping source to drain (I cant remember what he said exactly) and I misunderstood this instruction as I thought he meant just flipping the mosfet and I knew from my past knowledge this not to be.
It's only two seconds ago that I positioned the load on the other side of the mosfet that I realised the whole problem with my circuit was an amateur cockup, and a result of me not concentrating and putting the mosfet on the wrong side of the load (lamp).
Therefore audioguru, despite all the ill feelings, does deserve the credit of being the person who had the right idea. I think it could have gone without the ill feelings, but I insist on being fair with the good aswell as the bad, so thanks. I do think you're an arsehole but thanks. You've had chance to say what you think, that was mine. We are even and this is done with.
Your suggestion too is appreciated though, this three page thread really is about the placement of a mosfet. I think we've all earned the right to feel daft. It is after all a basic circuit, and as far as placing mosfets goes it's one I've done before.
As far as this thread goes, my solution that I drafted myself was good, the circuit was no-one elses suggestion, I never really understood what audioguru was raving about, but now I've fixed the problem myself by realising my cockup maybe I can. I assume he was trying to get me to look at that but between all the tripe I never got the message. But I sorted it. And I am content with
myself.
Interesting though that the circuit itself did 90% work despite the faulty placement.