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Recent content by LucasBS

  1. LucasBS

    Help on a darlington

    Awesome, man Worked perfectly. 3nF did the trick. No heating at all. Good to know about this harmonics handling method (we all know how to get rid of noises, but some of us need a reminder sometimes) Good to know about this SG3524 too. Although this capacitor trick is an elegant and cheap...
  2. LucasBS

    Help on a darlington

    I gave up and migrated to PWM It works good. Only two FETs totaled on the process (that's a win [dazed]) But as predicted, there is no such a thing as 0% duty cycle, so the light never goes off There's 1% or something close, but no zero Kudos to whoever solves this. No idea came out of me. I...
  3. LucasBS

    Help on a darlington

    "The part is rated for 0.6W, and you are attempting to to dump 2W into it?" I didn't see that ! Or did not remember that controlling only the current was not enough "Consider using a FET instead." Heard FETs dissipate too much when working on a linear zone The following would fix it: "I...
  4. LucasBS

    Help on a darlington

    Despite the risk of being cast back to school, I'll ask help on this dimmer circuit for a LED strip I have: - MJE13003 - http://www.onsemi.com/pub/Collateral/MJE13003-D.PDF - 2N3904 - https://www.onsemi.com/pub/Collateral/2N3903-D.PDF - 1k and 10k pots available - Many resistors This MJE...
  5. LucasBS

    Help designing a dimmer

    >Big correction: it's around 31A (7kW)< BTA41 is the triac currently present in the circuit I intend to rebuild. I don't know if the triac is the faulty component, but if it is, an overtemperature might explain the defect. Followed by the spikes caused by the diac. The good news is that it is...
  6. LucasBS

    Help designing a dimmer

    Anything you find helps Thank you, by the way It's near 40 amperes, actually But that's a problem for the triac
  7. LucasBS

    Help designing a dimmer

    I've been trying to explain the low peak voltage and found out that a series of factors lead to it, being the series resistor (even a small resistance reduces the voltage that much, depending on the arrangement), the capacitor (it has a resistance in AC, therefore producing a divider), and...
  8. LucasBS

    Help designing a dimmer

    The following pictures are from a simulation. The result/values are very close to reality. (Excelent and lightweight simulator, by the way: EveryCircuit) This first picture here is the ideal: Works well from cutoff (not depicted) to span (as represented). But you can see the current...
  9. LucasBS

    Capacitor only filter for a twitter

    Yep. Loudspeaker is the subject [lol] Blame it on regionalism... But I've learned a lesson here: I can cheat a similator, not real life My "infinte resistor" approach that I used on the RC calculator demands in real life a huge capacitor Let's try your LC idea now. Makes more sense
  10. LucasBS

    Help designing a dimmer

    220V Availability is the problem I live in a small town of a sh!t country, and it takes 40 fold or more the price of the pot to ship one of these I could accomodate a bigger pot, but it would be a lot of plastic breaking and glueing But was it 1M ohm, wouldn't it suffer the same problem (high...
  11. LucasBS

    Help designing a dimmer

    I need to design a dimmer, but I'm having a problem with the potentiometer, that heats up too much It's 150k, and it's practically impossible to get a different one The same problem goes to the diac/zeners: also difficult to get a different one. Right now I'm using the DB3 diac, that conducts...
  12. LucasBS

    Capacitor only filter for a twitter

    "There are many (2-way) speaker designs where the only cross-over is that the tweeter has a series capacitor." That's what I thought. It makes all the sense. I have no documentation at all. All the components I have been scavenging. The box I'm doing myself This small speaker is one of those...
  13. LucasBS

    Capacitor only filter for a twitter

    But what about the capacitive reactance ? Won't this reactance slow down the speed at which the low frequency fills the capacitor ?
  14. LucasBS

    Capacitor only filter for a twitter

    I need to make a High pass filter for a twitter (allowing 1kHz or more) I thought about putting a capacitor in series, but been reading that it needs a resistor too None of the answers have convinced me of why Plus, a resistor across (?after or before the capacitor?) will (?) reduce the...
  15. LucasBS

    Basic channel selector request

    Relay it is, then [cry] The volume that comes from the devices are already low IMO, cannot lower it more. I was thinking about economy and lifespan, but no problem: The relay will stay the very most of the time in one position anyway Good to know about this FET to ground option. Learned a...
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