I am not consered with the logaritmic scale. I wanted to ask about
the leds and th driver transistors, how this works, and if A and B
signal switch, as otherwise, I see no reason why someone would
start using A B C etc to denote nets.
Believe me, it's far better to do that than have traces going from
one side of the schematic to the other merely to connect those
points (as opposed to a line that is being used throughout the circuit,
such as the power supply line). You either have to have those long
connections riding over all kinds of things, or have them go far out
of the way just to keep it clear of the rest of the schematic.
It's really clear, once you know this is happening (and I admit that
in this case, it wasn't so clear because of the way the schematic
wsa drawn). The way I saw it when I was a kid was to have a triangle
on it's side (so the point faces left or right) and then the other point
has a similar triangle pointing towards the first one. It was then pretty
obvious that they were two points to connect together, because they
were special symbols for the purpose.
You can even do it so there is one source, and multiple "receivers",
which can be useful for showing where the power supply line goes, again
so you don't have long traces all over the schematic. In essence, that's
just a variant on the ground symbol. You know those all connect together.
The thing about schematics is that they should be drawn so you can
easily interpret them by looking. THis is not the same thing as circuit
layout. If you drew them the way you'd wire a circuit, it would usually
be a real mess to follow, yet the schematic properly drawn spreads
the circuit out so two points that might on a circuit board be next
to each other are at opposite ends of the schematic.
MIchael