1. Post #161
    Gold Member
    Chryseus's Avatar
    February 2009
    2,467 Posts
    After much thinking and testing I've come to the conclusion that the strange step in my oscillator is due to the rather low slew rate of about 8us per V, add the parasitic effects of my breadboard to that and it's going to be much worse.
    Now I just need a BiJFET or JFET op-amp with a fast slew rate to verify I'm right.
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  2. Post #162
    LoneWolf_Recon's Avatar
    May 2011
    1,856 Posts
    Wouldn't a BiCMOS op-amp work? Or is it just not as fast as a BiJFET?

    POWER..UNLIMITED POWERRRR:



    It was a pain in the butt to find that panel mount DC jack...
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  3. Post #163
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    I've got a full box of 2x110V / 2x12V Transformers, I should build myself a rail to rail PSU.
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  4. Post #164
    OrYgin's Avatar
    November 2007
    752 Posts
    It's been a week since i ordered on Sparkfun and the order is still on «Invoice Printed», Is it normal that it's this long ?
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  5. Post #165
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    You should contact them I guess
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  6. Post #166
    Gold Member
    Chryseus's Avatar
    February 2009
    2,467 Posts
    Wouldn't a BiCMOS op-amp work? Or is it just not as fast as a BiJFET?

    POWER..UNLIMITED POWERRRR:
    It was a pain in the butt to find that panel mount DC jack...
    Yes BiCMOS would work as well but as far as I'm aware they are not as common as BiJFET, JFET or CMOS, I might just be talking out of my ass however.

    Anyway
    What is the battery for ?
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  7. Post #167
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    That's where the power comes from duh
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  8. Post #168
    Gold Member
    Chryseus's Avatar
    February 2009
    2,467 Posts
    That's where the power comes from duh
    Then what is the DC jack for ?
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  9. Post #169
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    Then what is the DC jack for ?
    That's the overdrive injector for more power
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  10. Post #170
    LoneWolf_Recon's Avatar
    May 2011
    1,856 Posts
    If in the case I wanted a standalone or mobile transmitter. The theoretical current draw from the circuit will be bout 90mA in which the battery wont last more than two hours.. I've finished half of the overall transmitter board but I think I may have broken the tuning cap by turning it too much.. :/

    Oh and Chryseus, would this work? Its slew is averaging bout 4uS, or is that still too slow?
    http://www.ti.com/product/tlc272
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  11. Post #171
    RISC MASTER RACE.
    MIPS's Avatar
    August 2010
    7,104 Posts
    What is the easiest way to cut square holes in project boxes?
    I bought a metal box for my chip programmer and need to make one large square opening for the TEXTOOL and PLCC sockets to stick through but I can't think of a way to cleanly cut the hole. I used a Dremel with plastic boxes in the past and the finished project looked like shit.
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  12. Post #172
    Gold Member

    March 2005
    3,028 Posts
    Uh. Try drilling holes at the corners, then connect the holes with the Dremel (I think this might be the wrong tool for the job :\). Clean up the edges with a file. Make the hole smaller than you need it, since you'll probably have to remove a lot of material with the file.
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  13. Post #173
    LoneWolf_Recon's Avatar
    May 2011
    1,856 Posts
    A square rule, mark the lines with a sharpie(Or a white marker for that matter), and cut four holes at the corners. Then take your Dremel and cut along the lines. If its a plastic project box, I recommend hand sanding to smooth it out..The Dremel's been too powerful on plastics(For me atleast) :/

    EDIT:
    You could adapt and follow this Tut:
    http://www.robotroom.com/WaterSoftenerMonitor2.html
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  14. Post #174
    Gold Member
    Zero-Point's Avatar
    March 2006
    7,671 Posts
    What is the easiest way to cut square holes in project boxes?
    I bought a metal box for my chip programmer and need to make one large square opening for the TEXTOOL and PLCC sockets to stick through but I can't think of a way to cleanly cut the hole. I used a Dremel with plastic boxes in the past and the finished project looked like shit.
    Might have to get a nibbler, but be warned, those things are a pain in the ass. Prepare for blisters.
    http://en.wikipedia.org/wiki/Nibbler
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  15. Post #175
    chipset's Avatar
    November 2010
    2,268 Posts
    Basically as everyone's already suggested, do the rough work with a drill and dremel and finish up with some tiny files.
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  16. Post #176
    SubbyV-2's Avatar
    January 2011
    273 Posts
    Dremels tend to get a little loose on plastic, they're pretty powerful, they do metal nicely as long as you don't rush and not trying to get the most out of your cutting discs (it suck's cause they're expensive)
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  17. Post #177
    chipset's Avatar
    November 2010
    2,268 Posts
    Dremels tend to get a little loose on plastic, they're pretty powerful, they do metal nicely as long as you don't rush and not trying to get the most out of your cutting discs (it suck's cause they're expensive)
    I don't buy Dremel brand accesories, yeah the quality difference is quite noticeable but I find the savings more than make up for it.
    If cutting a piece of metal takes two dremel cutting wheels and 6 cheap-ass ones, and the cheap ass ones cost 1/4 of the dremel wheels, it equals quite a bit of money saved in the long term, only downside is changing the damn things is quite annoying.

    Also cutting plastic isn't a problem unless you cheaped out and got a rotoraty tool without variable speed. I got a Dremel 4000 so I just turn the revs down to about 5k-10k and use a pistol grip handle for extra control, as well as using both hands on the dremel and using a vice to hold whatever I'm cutting.
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  18. Post #178
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    I think my dremel is broken, it randomly changes it's RPM every few seconds
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  19. Post #179
    Gold Member
    Chryseus's Avatar
    February 2009
    2,467 Posts
    Oh and Chryseus, would this work? Its slew is averaging bout 4uS, or is that still too slow?
    http://www.ti.com/product/tlc272
    I think you mean 4V per μs, but yes that would probably do the job.
    Although I'd go for something a bit faster such as the BiFET THS4631 which has a slew rate of 1000V per μs, probably overkill but meh.
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  20. Post #180
    Gold Member
    ddrl46's Avatar
    October 2007
    3,685 Posts
    Toooob



    Yes I know my sensor is dirty, I found out after I took these pictures
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  21. Post #181
    Gold Member
    POLOPOZOZO's Avatar
    May 2006
    14,997 Posts
    Hey you know what's fun constantly burning yourself with a soldering iron shaft out of clumsiness.
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  22. Post #182
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    Hey you know what's fun constantly burning yourself with a soldering iron shaft out of clumsiness.
    I did that once, and only once.
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  23. Post #183
    Gold Member

    March 2005
    3,028 Posts
    I was trying to pry free the leads of a resistor with my iron once (they were bent over and soldered, so it didn't want to pop straight out). My iron's tip is freshly-sharpened-pencil sharp, and I was putting a good amount of force on it. So I ended up stabbing my thumb full-force with a 300C iron, and had a big black lump of dead tissue under my skin for like a month.

    And now I don't pry things with an iron.
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  24. Post #184
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts


    They save lifes!
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  25. Post #185
    LoneWolf_Recon's Avatar
    May 2011
    1,856 Posts
    Hey you know what's fun constantly burning yourself with a soldering iron shaft out of clumsiness.
    Is it bad if I'm hallucinating that my soldering iron smells like a Reuben?
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  26. Post #186
    Gold Member
    Lapsus's Avatar
    June 2006
    1,080 Posts
    Just don't try to take a bite out of it and you'll be fine.


    Hey you know what's fun constantly burning yourself with a soldering iron shaft out of clumsiness.
    I only managed to stop doing that after grabbing the wrong end of the iron once. I didn't get it too badly, fortunately, I just had to write left-handed for a while.
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  27. Post #187
    Gold Member
    Zero-Point's Avatar
    March 2006
    7,671 Posts
    Only time I've burned myself like that was my soldering iron and stand fell off my desk whilst the iron was hot.
    Grabbed the iron by the cord ironically enough but I grabbed the metal spiral part of the stand. :gonk:
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  28. Post #188
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    The worst thing that ever happened to me was that exploding battery that hit my eye, and I cried afterwards.
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  29. Post #189
    Gold Member
    Van-man's Avatar
    August 2009
    15,159 Posts
    Hey you know what's fun constantly burning yourself with a soldering iron shaft out of clumsiness.
    My left hand is full of small scars from all the times I've had that happen to me.
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  30. Post #190
    Follow me on github!
    benjojo's Avatar
    January 2009
    2,622 Posts
    I remember talking with ddrl46 once on skype and then his boost converter exploded and it filled his room with smoke.
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  31. Post #191
    chipset's Avatar
    November 2010
    2,268 Posts
    I have more tiny scars and knicks on my left hand than I care to count form various mishaps with screw drivers, pliers and most of all, knives.
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  32. Post #192
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    I once stepped on an upside down IC. Barefoot.

    I can truly say that my blood went into that project.
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  33. Post #193
    Gold Member
    POLOPOZOZO's Avatar
    May 2006
    14,997 Posts
    My left hand is full of small scars from all the times I've had that happen to me.
    Oh yeah, well this time I got a burn with the same hand I was holding the iron with, top that!

    Edited:

    It's almost as bad as trying to sew by hand.
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  34. Post #194
    Gold Member

    March 2005
    3,028 Posts
    Does it bother anyone else that today's Google doodle (in honor of Hertz), is elliptical rather than sinusoidal?
    Undesired harmonics.
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  35. Post #195
    Gold Member
    Chryseus's Avatar
    February 2009
    2,467 Posts
    I thought it looked a bit odd.
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  36. Post #196
    Gold Member
    ddrl46's Avatar
    October 2007
    3,685 Posts

    This might take some time to reassemble (broken lens detection lever on Canon EOS 1N)
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  37. Post #197
    www.bff-hab.de
    Dennab
    February 2009
    7,832 Posts
    Yes, I hate it when sines are drawn with vertical flanks. They're not supposed to be vertical.
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  38. Post #198
    Gold Member
    Tw34k's Avatar
    January 2012
    697 Posts
    Note to self: Never take apart a DSLR
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  39. Post #199
    Gold Member
    ddrl46's Avatar
    October 2007
    3,685 Posts
    Note to self: Never take apart a DSLR
    This is an analog SLR, digital ones probably aren't as bad.
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  40. Post #200
    Gold Member
    Tw34k's Avatar
    January 2012
    697 Posts
    I would hope so, that thing looks like a nightmare.

    Edit: For content sake, here is a crappy cell phone pic I sent to my buddy to show my new iron that arrived yesterday.

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