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  1. BGB

    Correct voltage translator

    maybe they gear it up, such that while the motor turns rather quickly, the encoder wheel reaches absurd speeds. or, maybe a GMR read-head and dense alternating north/south lines or similar. or, more likely, the numbers are a bit off...
  2. BGB

    OT? Volt/Amp/Watt fundamentals (and simulator issues).

    yeah. though, voltage by itself makes more sense in many cases. say you have a battery: you have a certain voltage at the terminals, and for sake of simplicity can be assumed to be constant (and/or, we can assume a fixed-voltage difference with an implicit series resistor); the amperage...
  3. BGB

    OT? Volt/Amp/Watt fundamentals (and simulator issues).

    in my electronics-simulator sub-project, stuff seemed to be ok when it only had wires. I could make wires, and short things between Vcc and Gnd, and saw plausible looking voltage drops and amperage values. then went and added resistors, which sort of work, but a bit of problem emerges: current...
  4. BGB

    Electronics engineering

    much agreed. it is one thing to understand in-theory how some components or circuits may behave, but some hands-on experience building things helps give a much better understanding of how the parts actually behave, and may help point out a lot of things which one may have overlooked in their...
  5. BGB

    Electronics engineering

    yeah, there is a lot of stuff in electronics: digital electronics, which are low-power and low-voltage, very sensitive to timing issues, moderately sensitive to noise; a lot of this involves working with ICs. here, things like component switching times, propagation delays, ... may become...
  6. BGB

    side: better simulators?...

    ADD: spent part of last night writing a simulator, and thus far it basically simulates wires (so, it is possible to effectively short between a voltage source and ground, and get crazy high amperage readings...). may get back to working on it, and adding support for some components (such as...
  7. BGB

    IC heating problem while using 24 volt smps

    usually a switching regulator would be used to produce the target voltages directly. there are pros and cons, typically the benefit is that they are more efficient (less of the power is turned into heat), but the disadvantage of generally being more expensive, generally most often in the form...
  8. BGB

    side: better simulators?...

    contents of a simple ".asc" file (dunno ATM how to attach files on here...). didn't have a prior circuit on-hand (one I could send was on my laptop, didn't feel like pulling it out and starting it up), but threw one together which still proves problematic. however, it seems after an update...
  9. BGB

    side: better simulators?...

    I don't think "LTspice freezes up" is normal circuit behavior (because... reality doesn't just freeze up). a lot of times, either one of: LTspice shows it as steady-state, but the real-life circuit oscillates (this has happened with some of my current-limiter attempts); it is an oscillator IRL...
  10. BGB

    side: better simulators?...

    ok. I had tried these before, and the oscillator would typically start going a little bit, but then usually stall out (say, I only get the initial rise of the waveform, and the simulation never completes). I had wandered off and came back, but it is still stuck at that point. I had looked...
  11. BGB

    IC heating problem while using 24 volt smps

    or, alternatively, use some heat-sinks and a fan (such as an old computer fan). I am using a 7805 to drive a 700mA load, but this depends on the fan operating. if the fan is not running, the 7805 fairly quickly goes into thermal shutdown. FWIW: the watt rating on a resistor does not mean that...
  12. BGB

    side: better simulators?...

    well, for a while I have been using LTspice, and it basically works, however: I would like to be able to run and tweak circuits in real time (or interactive sub-real-time, say, 1000x slower than real-time), and don't like having to manually re-simulate; I would like something that doesn't freeze...
  13. BGB

    dual electromagnets

    I think, it depends: for the external net field, probably. the fields should mostly cancel out if they are opposite and fixed in place. if the coils can move freely, and the field strength is high enough, one may see some movement. the presence of a steel or iron core on the inner coil...
  14. BGB

    LM317 voltage drop

    for running something like running a Raspberry Pi, I have a 9v brick of AAs I had been using as a backup. this can supply a little more current. a PP3 battery may not be sufficient for this. another possible issue is the regulator overheating, in which case it may not be able to supply enough...
  15. BGB

    fried L298N, stepper motor fun...

    driving the stepper with a BJT H-bridge, at 5v, it will hold at about 1A or so (and holds pretty solid), but if it tries turning (say, at 100RPM), current draw drops to about 0.25A, and the motor has almost no torque. at 9v, at full duty, it will pull about 3A trying to hold, but around 1A...
  16. BGB

    Safety measures when working with electronics?

    1. yes, soldering iron may quickly cause burns. though, FWIW, I have personally managed to more often burn myself worse with a glue-gun. use caution if soldering around hot-glue, as the iron may also melt the hot glue, which may become very hot and sticky. 2. or, if you do, take precautions...
  17. BGB

    Series regulators in parallel

    I have wired a pair if LM7805s in parallel before, and haven't noticed any big difference between one and two of them. with one of them, it gets hot, and may eventually go into thermal shutdown. with two of them, both get hot, and thermal shutdown seems to happen after nearly the same amount...
  18. BGB

    fried L298N, stepper motor fun...

    I have some MOSFETs, but nowhere near enough, and they cost a lot more than using Darlington transistors. heat and loss isn't a huge factor here, and I wont be running them anywhere near full load (running too much power continuously would be bad for the motors). I had used some MOSFETs to...
  19. BGB

    fried L298N, stepper motor fun...

    well, back to this (after a good long while). my past attempts at current limiting the L298N (with improvised analog electronics) were ultimately not successful, and eventually the thing fried. couldn't really get accurate current limiting, and the stepper kept trying to pull more current than...
  20. BGB

    stranded wire max.current

    from my experience (fairly limited, not had "that" many wires fry, at least unintentionally): 7-10A seems like a good limit for 22 AWG wire (copper). though, running 6A through 22 AWG, or 4A through 24 AWG, voltage drop may be an issue (AFAICT: for a pair, ~ 1v every 4 feet or so). in this...
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