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  1. KrisBlueNZ

    Circuit to indicate charge remaining in any battery bank

    Estimating the amount of energy in a battery is difficult because of factors such as temperature and the age and condition of the battery. You can try to estimate it by measuring the battery's terminal voltage, with no load and/or with a known load, but both of those factors affect the result...
  2. KrisBlueNZ

    IR diode+Photo diode sensor for Tachometer

    The capacitor (C1) is needed to make a short trigger pulse for the 555. D1 is a good idea, to avoid feeding a +24V pulse into the trigger input. D2 isn't needed. If the LED and photodiode are part of a photointerrupter, you probably don't need high sensitivity. You can increase the trimpot if...
  3. KrisBlueNZ

    Dynex DX-L42-10A Intermittent Issues

    It's possible there's a faulty via. The through-hole plating can fail. Yes, if you can take some really clear, zoomed photos, that would probably help. I would like to confirm that those components are definitely supposed to be connected together, before I suggest that you connect them together...
  4. KrisBlueNZ

    Stage Line 500W amp repair project

    I said that the fan is controlled by temperature on THAT model, not necessarily on other models. Yes, but check both channels equally carefully. If there are dry joints on one, there are probably dry joints on the other; the only difference is that they happened to get bad enough to cause a...
  5. KrisBlueNZ

    Mosfet bridge safety

    The sources both point downwards.
  6. KrisBlueNZ

    Stage Line 500W amp repair project

    I think it might not be a good idea to just fix the dry joints then power it back up without doing any checks. In audio amplifiers, especially high-power ones, all of the semiconductors in the output stage are tightly interconnected and any fault often causes failure of all of them. The Fault...
  7. KrisBlueNZ

    Dynex DX-L42-10A Intermittent Issues

    It's clear from the schematic that C626 and C621 are supposed to be connected in parallel. So I don't know how it's possible for them to have different voltages (3.32V and 1.6~2.0V) on their non-0V ends. As you say, it's as if there's a resistor between them. So now you need to look at the...
  8. KrisBlueNZ

    Mosfet bridge safety

    Not according to the schematic. And driving the low-side ones directly from a micro, especially at only 3.4V, is also silly. steelgoofy, look for high-side and low-side MOSFET driver ICs. Digi-Key (http://www.digikey.com) has a wide selection.
  9. KrisBlueNZ

    Can I add an Aux. input to my RCA super radio?

    Gryd: Snap!
  10. KrisBlueNZ

    Can I add an Aux. input to my RCA super radio?

    I don't know why he connected a resistor from the AM antenna to ground. Perhaps he isn't using AM at all, and wants to avoid noise if AM is accidentally selected. There is some variation in design between models and manufacturers. The principle of interrupting the normal audio and inserting new...
  11. KrisBlueNZ

    The art of electronics

    I recommend it.
  12. KrisBlueNZ

    Stage Line 500W amp repair project

    Wow, that's a pretty impressive looking amp! And thanks for the details and history in the first post. This could be important. Where is this blown component? Is it somewhere in the second picture in post #4? I don't see anything obvious. Dry joints are a common cause of problems. Also...
  13. KrisBlueNZ

    Mosfet bridge safety

    That won't work. Read my post #11 until you understand it.
  14. KrisBlueNZ

    Dynex DX-L42-10A Intermittent Issues

    OK, so the manufacturer installs either L604 or L620 but not both. That's reasonable, and it explains why the schematic appears to show the MST3.3V and +5V rails being connected together, although the schematic should include a note saying that only one of them is installed. Those values for...
  15. KrisBlueNZ

    Theory of operation of MS3110 high resolution capacitive sensor

    Repeatedly opening the same topic in NEW THREADS is not boring; it's INAPPROPRIATE. Harald warned you after the third time you did it; this is the fourth time, so I'm giving you a week to think about WHY discussions on one topic should not be split into four separate threads. Edit: I've merged...
  16. KrisBlueNZ

    Power Amplifier Looking for improvements

    Anti-thump circuits also monitor the AC from before the bridge rectifier and use a monostable or similar circuit to detect very quickly when the mains has disappeared, so they can drop out the relay before the main supply rails have had time to discharge. Google anti-thump relay circuit.
  17. KrisBlueNZ

    Capacitive Reactance Circuit

    I would be very interested to know what's inside that module. Based on the price, USD 0.99, my first thought was that it IS actually a capacitor-fed power supply, in which case it's more dangerous than what I propose because its capacitor will have a much higher value (to achieve 300 mA output)...
  18. KrisBlueNZ

    Can I add an Aux. input to my RCA super radio?

    I've fixed the thread title. Yes, we'll need a model number and a readable schematic. That one is "essence of schematic".
  19. KrisBlueNZ

    Problem faced in generating more i/o's through AVR

    Great explanation Steve! I was trying to understand how it works by looking at the ON Semi data sheet but it wasn't very clearly explained. So the output latches are transparent; they follow the shift register while STROBE is high? That's interesting. It's a shame there's no reset function...
  20. KrisBlueNZ

    Promote a post!

    hevans1944 again, describing how effective resistance and torque are created and vary in DC brushed motors: https://www.electronicspoint.com/threads/confused-about-a-dc-motor.270983/#post-1628314
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