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  1. C

    Can anyone explain how this battery charger works?

    that's definitely a thermistor ntc or ptc, is it there to prevent an inrush or is it there to decrease current are you positive your circuit is correct?
  2. C

    SMPS feedback compensation with error amp simpler than type 1?

    on a low voltage buck converter the output will have a resistor divider across it, the voltage might be so low it needs to be amplified via an opamp first, no clue why they call them error amplifiers though, and if a voltage threshold is high enough a signal is sent back to the regulator to hold...
  3. C

    Why does zener voltage decrease as series resistor increases?

    https://everycircuit.com/circuit/4952165921325056 I just knocked up this very quick design for you, it's way more stable than relying on a zener alone a single 2n2222 npn would do the job if you keep it under 500ma or so
  4. C

    Is voltage negotiation required?

    I tried editing the post but it said i couldn't... so would 9v melt it? would it refuse and not charge? or would it be happy if I placed a 9v battery across the usb rails? .. place your bets!
  5. C

    Is voltage negotiation required?

    VHCA VHAN VH H3D can't find a datasheet :/
  6. C

    Is voltage negotiation required?

    yes and me, as I don't have a backup phone I'll do it in a few months when it's time to upgrade lol as for the regulator, I expect them to be a buck regulator and switched via and inductor capacitor combo to a lower voltage either way, my gut feeling would be it works, another option is to find...
  7. C

    Is voltage negotiation required?

    um yes, dinosaur days, it used to be 500ma, now the bare minimum is quick charge which relies on QC3 and delivers about 15w of power, I'm working with PD or power delivery which outputs at 20v over usb c at 3+ amps but my phone is a bit old lol, it's about 5 years old and only supports 9v...
  8. C

    Is voltage negotiation required?

    yes I do risk... hence the question.... that said! the same 5v rail and 9v rail is shared, that would imply the step down regulator is happy to take up to 9v, the phone charger ic should regulate current and step it down hence the question, I have seen a dynamo from china which allows you to...
  9. C

    Is voltage negotiation required?

    what are you on about? it negotiates voltage, current will be the maximum the cable can supply and the ic charger will pull.....
  10. C

    Is voltage negotiation required?

    My phone will charge from 9v once it negotiated with the charger to step up 5v to 9v be wall charger or power bank so what happens if I simply dial in 9v and feed it directly in? would that give me fast charge?
  11. C

    Physical difference between low/high transformers?

    I'm obviously of the few who use a mobile device to type on and android auto corrects it without my knowledge hence that typo...
  12. C

    Physical difference between low/high transformers?

    Different core material is the answer... after all copper wire is still just copper wire nothing else is different. .
  13. C

    Physical difference between low/high transformers?

    You answered the question by explaining a different core was used, thank you...
  14. C

    Microwave Transformer Step Down

    Yeah i've seen how thick it is... mental lol
  15. C

    Components Buyers Guide [for Dummies]

    Buying in components just for hobby use is quite extensive, let alone more special ics and components as a hobbiest you'd never need.. As for using a smaller inductor you can do that but the load had to be significantly smaller to not burn up the wire
  16. C

    14.8v @ 16 amps down to 12v @ 8 amps

    I'm not sure there's enough give for a regular 7812, you'd need the LDO version, then on top of that you'd need to load balance them or 1 regulator will have a higher voltage and that will dump all it's current to the camera and the other regulators get cold Say 0.1ohm on each 7812 out to limit...
  17. C

    Power consumption calculation

    Mixing two battery chemistries to produce 5v surely can be done, this battery is close at 4.5v
  18. C

    Power consumption calculation

    Nobody makes a 5v battery... yet lol
  19. C

    Physical difference between low/high transformers?

    I tried googling it, but it's obscure .. Is there a pychical difference between a high frequency transformer and a low one (mains 50/60hz) Are the cores different? Eg what happens if i take a huge old transformer designed (and by this, precisely what is the difference?) For mains and...
  20. C

    Microwave Transformer Step Down

    Anyone ever tried that? Using an old transformer replacing the secondary winding with a thick copper core cable and just wrap it the few times you can to get huge amps low vac? I guess a high frequency switch mode transformer is more efficient for this job... But anyone here ever done it...
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