Re: How do you design a circuit?

ku7485 wrote:
This might be a dumb question to some. I've been reading a lot about
electronics, but never find a good piece of text that properly tells
about how to design a PRACTICAL circuit. I've seen some basic examples
such as connecting a LED, resistor, and a battery and using Ohm's Law
to determine to right resistance, but that's about it. I never have
heard why an engineer explain how they built their own circuits and why
they chose these parts. We'll anyway, I'm just wondering how people
are able to design.

i'd say it comes in bits and pieces.

you never really know where those pieces will come from. you might be
reading something one day and they are explaining binary logic in 8051
assembly language and some kind of light comes on that all of a sudden
makes the stuff you read about AND gates 2 months earlier make sense.
or you might be trying to figure out how to partition your class-C
network and have to teach yourself how to convert decimal to hex and
all of a sudden realize that it's easy to convert to binary and make
the connection back to how to use address lines on an old processor to
generate a chip select signal. maybe you're working on your sailboat
and figure out you need 5 volts instead of 12 and you try to use a
transformer but it doesn't work ... then you're sitting on the plane
back to your home after a long week in cleveland and some sales guy is
talking about voltage regulators and you don't have any idea what that
is so you look it up and Aha! 5 volts from 12 volts. and all of a
sudden you realize what that box was on the generator in your old
triumph when you were young lol.

certain you're doing the right thing by reading, and by asking here,
and hopefully by just getting tools and chips and fooling around with
them to see what happens. make that LED circuit, try to figure out how
to make a voltage divider, get some PIC processors and a cheap
programmer and start fooling with that. get a soldering iron and try
to put some kind of a circuit together that does something.

some here have said go to school to learn, that's a good idea too.
some say start with the desired result and work backwards, that works
too. come at it forward, backwards, 10 different ways sideways and
underneath. talk to folks, get annoyed when you burn something up,
laugh when it works right, smile, raise an eyebrow. toss rags on top
of it and walk away from it for a month, or two, and come back later
and try something else. learn a little bit here and there while you're
not even really trying, or try a big project and learn through the
effort, even if it fails. pick old chips off of boards in the house,
rip the motherboard out of that old laptop in the closet and start
soldering things to the parallel port pins. install linux while you're
at it. get an amateur radio or make one, or find some old hermit ham
tediously adjusting his antenna and walk up and start talking to him.

when all else fails i'd recommend getting a voltage regulator and start
plugging chips into a solderless board, maybe start with an op amp, and
figure out what that does. or visit some chip manufacturer websites
and start reading over the datasheets, you'd be amazed how many
fantastic things you can do these days with some fancy ass chip that
you hook 5 volts to and connect two or three lines to a processor.

.