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Re: LMD18201
Back in the Creataceous Era when I was a young person I always wanted to design everything myself so I could avoid spending all the money that I didn't have.
It took me a long time to get it through my head that I can buy stuff cheaper and easier and I can design/build it. I would love to design and build a car engine from a block of metal, but I can buy one cheaper and easier.
But now (when I'm not working my day job as a designer) I still spend a lot of time designing and building (or rather helping students do that) robots and stuff.
What you will find is that it is really useful to learn about the things one the links I gave above. Any of that material that you can absorb will come back and help you later, somewhere, somehow, if you are interested enough.
In practice, especially at larger volumes, circuits are developed like the ones in the links above, using parts from supply houses, and then the circuit is condensed into a single ic at a fab house for commercial use.
I wish you had access to an O'scope, a signal generator, a breadboard, a small motor, and some parts. You could have a blast on a benchtop working out all these exercises and really wrap your head around these issues. And have a lot of fun even though you may or may not really complete a motor controller. Being able to 'see' your signals and workout prototypes on a breadboard will tremendously help you gain knowledge and skills.
( Back "in the day" I once built a computer terminal (pre-PC) and a modem. The modem had an acoustic coupler made from a John Deere tractor radiator hose and was encased in a wooden box made from leftover beehive parts. )
If you designed a PWM system from scratch if may look very different from what it does today. But, the signal formats were set years ago to accommodate issues of that day that are probably no longer in existence. So we are stuck with backward compatibility issues.
Modern phone systems have a similar problem. Central Office telephone systems have to be compatible with signaling systems that go back 100 years. This gives phone engineers similar grief.
I hope everyone reading this thread gains an appreciation for how much value are in the Victor speed controllers. There really is a lot more to it than it appears.
If all that answers were really simple, then we wouldn't need the engineers would we?
Ed
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