Errors

More About PWM


Update 3/16/13: Ok, my graphs (and some conclusions drawn from them) had a serious flaw. I’d modeled both the growth and decay curves incorrectly, and this caused current to drop to zero in a lot of situations where it wouldn’t have. Don provided an interesting simulator model, which led me to do some more reading and correct my model. It’s still not complete, but rather than re-do this post, I’m adding a new one that is the correction. I’ll leave this one here for history’s sake, but please see the new one.
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In Search of the Perfect Post

One of the hardest lessons in model-railroading, at least for me, has been that “good enough” really is good enough. I spent fifteen years on my HO layout doing very little, in large part because what I did do fell short of what I’d set out to do, and I’d get frustrated and go do something else for six months. With Sumida Crossing, I started with the premise that I wasn’t trying to do a picture-perfect layout of the kind featured in magazines. Neither my skills nor my available time were up to that. Read More...

How Not to Make Backdrops

I bow to no one in my ability to screw up a simple task. Complex tasks, no trouble, but the bleedingly obvious escapes me every time. Case in point, the backdrop photo on the right above, which you’ll note is nearly a foot higher than the backdrop it’s supposed to be attached to. There’s a story here.
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Measure Twice, Cut Once, Get it Wrong Anyway

Some days it doesn’t pay to go into the railroad room. I had spent the weekend carving foam for the hillside that separates the Urban Station scene and the Riverside Station scene from the large river. Just before I was ready to glue it down, I decided to check the clearance of my subway tunnel, and found it seriously wrong. After realizing that my “two-inch” insulation foam was 1.75 inches thick (and I’m sure I measured it before), and raising it up with a chunk of gatorboard (barely visible above, on the left below the pink foam), I still had a bit of a problem. Read More...