use 4 tl074
or 8 tl072 if it works better for the layout
tl082 are cheaper, prob work fine for this
you prob need bipolar rails tho
theyre not rail to rail, need a negative rail
this is a good project to research opamps, look into rail to rail stuff, decide what kind of temp range you want this thing to work in
kevtris: haha @ LED circuit + two bus wire jumpers
Posted by renesis at 12:05 | permalink | 0 comments
yeah run lower voltage on the coils if you can
if you want to build something yourself, something like: http://www.uchobby.com/wp-content/uploads/2008/02/opamptransistorsink.gif
with a better voltage reference and a way to ground out the ref voltage
but it will waste as much power as resistors
its just adjustable
you could pwm a filter for the vref and do microstepping with it
ha 'analog microstepping' with like a 8b or 10b pwm value ramp
1000x microstepping
Posted by renesis at 11:58 | permalink | 0 comments
http://www.uchobby.com/wp-content/uploads/2008/02/opamptransistorsink.gif
thats more what i would do
this doesnt need to be adjustable current tho, does it?
well this is going to be just as much loss and heat
itll just be stable about it
you cant use lower voltage?
and there are IC that do switch mode current reg
if you dont want to waste power, figure out what voltage the motors run at the current you want
and just use the darlingtons to switch the coils
Posted by renesis at 11:53 | permalink | 0 comments
sensing on the collector side seems like more drama
you could sense on the high side of the load, and drive low side, but PSU ripple might make that less than stable
as long as your voltage ref and current sense resistor were close enough it should be okay
Posted by renesis at 11:48 | permalink | 0 comments
http://www.ti.com/ww/en/bobpease/assets/AN-31.pdf
well do you want one or do you want 4 circuits?
page 13
precision current sink/source
ha
oh hmm nevermind
for your circuit you can maybe direct drive the darlington
beefy opamp
and no common emitter wont work
Posted by renesis at 11:43 | permalink | 0 comments
they call tooltips bubble help
kk
i do not see this option
either gone from new version (it showed up in v5) or i hallucinated
hmm
for how much current?
and sec there is a national doc with opamp circuit that can prob do it
Posted by renesis at 11:37 | permalink | 0 comments
the germans have some odd ideas about UI, but their code seems to be pretty tight
yarly, im pretty sure most of my annoyances with eagle have been missing functionality, or intended operation i just didnt agree with
im not sure ive ever been fucked over by a bug
could say for sure 100% but nothing i remember
*couldnt
i rabbed
fuck that shit
i used that right around when i was fucking with ultiboard (ewb)
and ultiboard has a really nice, super intuitive UI
bit slow but very functional
orcad was like driving a traktor or something
orcad felt like a legacy app from the mid 80s
right and im like fuck that
i dont know wat wingdi is
im not an er337 open source programmer like you mr cop
i think they have opengl now
something else
maybe i have that shit installed sec it is described in a checkbox thing
Posted by renesis at 11:31 | permalink | 0 comments
its console cad, so it kind of has this acad feel to it
its actual cad funtions are pretty weak tho
all of everything?
that shit is too my little pony
ill try it out next thing
everything kind of works timecop
you didnt like eagle lib editor
and you were using lines instead of traces
and you ragequit it
no one does for like 3 years
but youre dumb because in here, with us feeding you to keep you quiet
prob 6 months
if that
tho you are not an artist
and dicktrace seems to work fine for you
so im not really sure how much value it would be to you, especially now
ive never known it to be buggy
Posted by renesis at 11:26 | permalink | 0 comments
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