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  1. chopnhack

    Op-Amp selection for inverting source signal - Bench PSU build

    LOL - it's negative in relation to the "higher" battery which is measured as a positive 1.5v. The center connection between batteries is common to both and the bottom is negative in relation to the first battery. I think I understand. I used two 9volts again and the panel meter measured the...
  2. chopnhack

    Op-Amp selection for inverting source signal - Bench PSU build

    Yes, I liked that most of what I was thinking about was covered and more! It does look like a good unit that will service my needs for - well for as long as I can tell. I was thinking of doing a fixed 5v and 3v for μcu projects - trivial, small transformer and two v-regs, but very useful. I do...
  3. chopnhack

    Op-Amp selection for inverting source signal - Bench PSU build

    That is a good point, I was just trying to use the two meters I already had. But if I can find small panel meters just for current, its worth another look. As for isolated, I had always intended to run these off of their own transformers. Edit: Found meter I found a meter - please have a look...
  4. chopnhack

    Op-Amp selection for inverting source signal - Bench PSU build

    Thanks Blue! Apparently, it's all been thought of before!! So reading the negative voltage using an op-amp will work! That's good to know :) I think I see the problem... the voltmeter uses one leg of the supply which is then used in the current sensing portion of the ammeter. Thanks for...
  5. chopnhack

    Op-Amp selection for inverting source signal - Bench PSU build

    I did try this, but it did not work - I like simple solutions too ;-)
  6. chopnhack

    Op-Amp selection for inverting source signal - Bench PSU build

    Hello all, I am looking for some assistance in choosing an op-amp to invert an incoming signal. Specifically, I am trying to use a panel meter to read negative voltage. I hooked up the panel meter to a supply and then tried to use the meter to read the value of a battery in reverse and it was...
  7. chopnhack

    Finding the smallest possible actuator, or a new solution. Help massively needed!

    Maybe contact these folks: http://www.piezomotor.com/ See if they can fashion a linear motor to push the rod up through the center of your rectangular column.
  8. chopnhack

    Bench Power Supply

    After much research today, availability of a matched set has been narrowed to LM317+/LM337- regulators. These would have a cap. of 1.5A of output current. Which is not bad in retrospect. My wants exceed my capabilities as always :p:oops:. I did find a nifty little board already made up which...
  9. chopnhack

    Finding the smallest possible actuator, or a new solution. Help massively needed!

    This might be an interesting method: https://en.wikipedia.org/wiki/Piezoelectric_motor
  10. chopnhack

    Finding the smallest possible actuator, or a new solution. Help massively needed!

    Is the 2x2x6 rectangular mass hollow or can it be made such to allow a thin bar to push up from below? The mechanism perhaps can be hidden below the rectangle? Does the entire apparatus have to be hidden inside the 2x2x6 rectangle?
  11. chopnhack

    Bench Power Supply

    I will continue down this road then. Thanks for the input. I will post a schematic later today. Yeah, I hate to black box that whole assembly as I am trying to learn, but if I just couldn't get it, I figured this might be a viable option if it even works!! LOL
  12. chopnhack

    Bench Power Supply

    Back to the LM350/LM338! Would it be wise to get one of each regulator from the same manufacturer? My thought was that if there were any small deviations, if the chips were from the same company they would be closer together in their variances. I see that the datasheet states built in short...
  13. chopnhack

    Bench Power Supply

    True, I didn't pickup on that! I too sometimes forget - two heads, two butts is how I try to recall it. Any thoughts on the previously asked questions?
  14. chopnhack

    Bench Power Supply

    Hi AK, I think I see what you mean in post #43 - the input of the negative regulator needs to be fed from the positive side of the bridge rectifier, while the output of the reg. is held to ground, this would leave the bottom rail to 'go more negative' as the regulator adjust to keep its Vref...
  15. chopnhack

    Bench Power Supply

    The LT1185 would not be a good choice, the unit operates at +2.5-25v above the reference voltage which is 7v. That means the psu would start at ~10V! That just wont work... Back to the LM350/LM338! Would it be wise to get one of each regulator from the same manufacturer? My thought was that...
  16. chopnhack

    Bose Car Amplifier Repair?

    Thanks Adam, I did test the diode that I thought was faulty on the back side, it measured the same as the other diodes nearby, about .5 V in one direction. Good advice, it may just be the corrosion causing the issue!
  17. chopnhack

    Bose Car Amplifier Repair?

    I had an issue with my car radio not playing any music whether CD or FM/AM was selected. I was able to narrow it down to the stock amplifier not working. (I disconnected amp and attached a tiny speaker to the pre-amp feeds and was able to hear music from each channel). I replaced the defective...
  18. chopnhack

    PCBweb Software?

    Welcome to the forums, Mike! Do drop by the Introduction's Thread and let us know who you are and what you are interested in. We can already tell you are passionate about EDA programs ;-) The post you quoted shows you that he did indeed try it and found it to be lacking. YMMV
  19. chopnhack

    Converting Switch/Case statement in C to ASM?

    Thanks for the responses guys. At this point, I would consider the advantages to be outside of my scope/skillset for programming.
  20. chopnhack

    I need to hire someone for a logic design

    Agreed - I recall this quote below from the first post: The battery backup is a necessity for aquatic life due to power outages!
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