Search results

Search Forums New Posts
  1. (*steve*)

    Acer X223W LCD Monitor

    To test the capacitors you'll need an ESR meter. In my experience, replacing the filter capacitors in the switch mode power supply of an LCD monitor solves about half of the problems with them. It's a cheap and easy fix, and my experience with Acer monitors is that it's not "if", but "when"...
  2. (*steve*)

    Why the crazy price for a decade resistor/resistance box?

    I was just pointing out that if you have 4 decades and you dial up 1002 then the 1000 needs to be better than 0.1% accurate (0.01%) would be better) or the last digit won't resolve. And it's the highest value resistors need to be the most precise. In the above example, a 1% resistor for the...
  3. (*steve*)

    Why the crazy price for a decade resistor/resistance box?

    If you imagine a 3 decade resistance box. If all decades are to be significant then the most significant decade needs values well within +/- 1%. That's not too hard, but for 4 decades it's 0.1%, 5 decades 0.01%, and so on. These resistors start to get very expensive. Cheaper decade...
  4. (*steve*)

    Acer X223W LCD Monitor

    It looks like you just quoted me without saying anything.
  5. (*steve*)

    fast optical switch circuit to turn on 3V 1A supply - please help

    When you say "switched in less than 1 microsecond", do you mean 1us from when light reaches a certain intensity, or that the load must be switched from off to on in less than 1us? Do you have anything other than the 3V you need to switch as a voltage to power the circuit?
  6. (*steve*)

    Getting full power output from 120VAC to 5V40A DC supply?

    You missed any useful description of the power supply. BTW, your calculation assumes 120mA per WS2811. <-- or very poor maths by me! :-(
  7. (*steve*)

    2 finger ECG circuit

    There's some huge capacitors in that circuit. Either that or you're using mF when you mean μF. There's only a factor of 1000 between them :-)
  8. (*steve*)

    Subaru dash clock problems - pictures...

    I'm not totally familiar with UK suppliers, but I'm pretty sure RS will be an option. Http://rsonline.co.uk Look up surface mount resistors. Then use the options to narrow down the options. You probably don't want to but 3000 of them at a time, you may have to buy 10 or even 100. Either...
  9. (*steve*)

    Shaker Charger Guidance

    Do a little research on what is required to charge lithium ion batteries. Try to determine what the fundamental rules are. You'll probably find that some of these rules are unlikely to apply to you (for example, do you think you'll need to be concerned about exceeding the maximum charge...
  10. (*steve*)

    Subaru dash clock problems - pictures...

    Interesting. It looks larger than 1206, and there's another one which appears to be the same size in the second picture (R18). And it may be the light, but one end of R18 may not be soldered properly... If I had to guess, I'd say a 1210 size 510 ohm resistor. However 1210 is an unusual...
  11. (*steve*)

    Subaru dash clock problems - pictures...

    R4 is apparently marked 511. That means 51 * 10^1 = 510 ohms. We know it's a surface mount resistor, but we can be longer see @Graphite's images so I can't tell you what size it is. If you can post a photo showing the pads with something nearby for scale (say, mm marks on a rule) then we...
  12. (*steve*)

    Shaker Charger Guidance

    You need something which will only allow power to flow from your shaker to the battery. So you know of a device that can perform this function? Is the polarity of the voltage generated always the same? If not, do you want to use both polarities? What could allow you to do this? It might be...
  13. (*steve*)

    Variac VA

    It's worth noting that for any load neither the VA or the current limit should be exceeded. Ok, you can exceed them a little for a short duration. But if you input voltage is 240V and your output is 20V, don't even think for a moment that you can use the VA rating to determine the max current...
  14. (*steve*)

    Help to fix HP5308A counter

    In general, you hook them up to power and the output does its thing. I went looking for the service manual and only found this. If you can find a more complete service manual it will often have schematics and a discussion of the operation of the various parts of the circuit. This would be...
  15. (*steve*)

    Resistor for power source minimum load

    That would be fine.
  16. (*steve*)

    Ultracapacitor protection/balancing board

    If low loss is your goal then you'll have to look at active balancing. One you see how complex this is, you might want to reconsider how important "low loss" really is.
  17. (*steve*)

    Calculating Heart Beat From Wrist

    This is homework, and we won't do it for you. What options have you considered? Have you investigated devices that do this (like a Fitbit)?
  18. (*steve*)

    SPICE alive

    I've not tried snorting LTSpice.
  19. (*steve*)

    Audio Amplifier Design

    Come on, he's only cut and pasted this query onto three sites as far as I can see. And given that he's replied to messages in only one (and seems to be getting somewhere) I think we can close this thread.
  20. (*steve*)

    Acer X223W LCD Monitor

    I'd open it up and look for swollen capacitors in the power supply. It might not be that, but it's a really good start.
Top