Although I can understand the routing of the circuit on the boards themselves, I still haven't learnt much about the circuit diagrams. I know that the white dots on the board denote the negative ends of the LEDs, because I worked out the negative end of the circuit diagram, and I now know that VC+ is the 12 V supply to the board and that VCC, the voltage common collector, is the adjusted voltage, which is 5 V on this board. I came to realise that the arrow heads on the diagram don't have anything to do with direction of electron flow or what is thought of as current; they just mean this part of the circuit carries on somewhere else! Oh, and I now know the symbols for LEDs, resistors, variable resistors, electrolytic and ordinary capacitors. And that's about it.
But I don't know how to count the pin numbers on the chip, for example. And I am confused by the power LED on this circuit - on my boards it is connected straight from the 5 V leg of the voltage regulator, and yet the diagram places a capacitor before it, either an electrolytic or ceramic, depending on which route you take.
Hmm, that really doesn't look like what's actually in front of me.
........................................unless this (below).......................really means this (below)?
And if so, why wasn't it drawn like that for clarity?
Finally, as promised, a costings update:
Farnell sub-total from separate orders = £54.88
- A3982 driver chip, part number 1521717, £4.60 and
- chip-leg cutter, part number 7256449, £39.90, combined VAT of £6.68
- IDC header, straight, 10-way, £1.61 each (x 2), VAT of £0.48
Running total (excluding set of washers and screws from B&Q) = £487.51